I have Python 2.7 as default however I also have Python 3.5 installed separately

```
 virtualenv -p /usr/local/bin/python3.5 kivyPy3.5

```

I am trying to setup Python 3.5 virtual env for kivy app development but I am getting the following error:

```
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/enum/__init__.py", line 371, in __getattr__
    return cls._member_map_[name]
KeyError: '_convert'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/virtualenv.py", line 23, in <module>
    import subprocess
  File "/usr/local/lib/python3.5/subprocess.py", line 364, in <module>
    import signal
  File "/usr/local/lib/python3.5/signal.py", line 8, in <module>
    _IntEnum._convert(
  File "/Library/Python/2.7/site-packages/enum/__init__.py", line 373, in __getattr__
    raise AttributeError(name)
AttributeError: _convert

```

How can I resolve this error?