RecursionError when comparing columns with a string beginning in "interval" on Debian
#### Code Sample

```python
import pandas as pd
d = {'col1': ['a', 'b']}
df = pd.DataFrame(data=d)
df.col1 == 'interval'  # works
df.col1 == 'bintervals'  # works
df.col1 == 'intervals'  # RecursionError
df.col1 == 'interval11111'  # RecursionError
```

Reproduced on python 2.7.15, 3.6.7, 3.7.0, 3.7.2 on Debian (using official Docker images), can't reproduce on macOS.

#### Issue Description

My use case involves using a very small DataFrame from a csv, whose columns will be compared against words in news stories. Recently, I noticed some `RecusionError`s in my server logs. After some digging, I discovered that comparing a DataFrame's column against a string that starts with "interval" causes the RecursionError.

The error appears to occur when the string starts with "interval" (no characters preceding it) and has additional characters after "interval". I'm not familiar enough with pandas to know why this could be happening. Are values starting with "interval" reserved for pandas' internal implementation of Intervals?

Strangely I can't reproduce the RecursionError on macOS. This issue could be related to Python on Debian, but the recursion loop does seem to originate in `pandas/core/dtypes/dtypes.py`.

My apologies if this is a duplicate issue that is already being tracked. I could not find any other reports of issues with this value, or documentation that states "interval..." is a reserved value.

#### Stack trace of RecursionError

<details>
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/site-packages/pandas/core/ops.py", line 1728, in wrapper
    (is_extension_array_dtype(other) and not is_scalar(other))):
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 1749, in is_extension_array_dtype
    registry.find(dtype) is not None)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 938, in construct_from_string
    return cls(string)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 899, in __new__
    subtype = pandas_dtype(subtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/common.py", line 2004, in pandas_dtype
    result = registry.find(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 89, in find
    return dtype_type.construct_from_string(dtype)
  File "/usr/local/lib/python2.7/site-packages/pandas/core/dtypes/dtypes.py", line 689, in construct_from_string
    if isinstance(string, compat.string_types):
RuntimeError: maximum recursion depth exceeded while calling a Python object
</details>

#### Expected Output

Pandas should not raise a RecursionError.

#### Output of ``pd.show_versions()``

<details>
INSTALLED VERSIONS
------------------
commit: None
python: 3.6.7.final.0
python-bits: 64
OS: Linux
OS-release: 4.9.125-linuxkit
machine: x86_64
processor: 
byteorder: little
LC_ALL: None
LANG: C.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.24.1
pytest: 4.3.0
pip: 18.1
setuptools: 40.6.2
Cython: None
numpy: 1.16.1
scipy: None
pyarrow: None
xarray: None
IPython: None
sphinx: None
patsy: None
dateutil: 2.8.0
pytz: 2018.9
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: None
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml.etree: None
bs4: None
html5lib: None
sqlalchemy: 1.2.18
pymysql: None
psycopg2: 2.7.7 (dt dec pq3 ext lo64)
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
gcsfs: None

</details>
