Importing submodels in pandas/core/series.py result with an error
#### Code Sample, a copy-pastable example if possible

```python
import pandas.core.ops as ops
import pandas.core.algorithms as algorithms

import pandas.core.common as com
import pandas.core.nanops as nanops
import pandas.io.formats.format as fmt

```
#### Problem description

The above code in series.py resulted with an import error. It can simply be replaced with:
```python
from pandas.core import ops, algorithms, com, nanops, fmt
```
Or however aesthetically pleasing. 