Getting the following error on MacOSX after installing Python 3.7.0 from the Python download. Also, tried installing from brew.

➜  ~ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from bin.test import *
>>> help(fetch_words)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_sitebuiltins.py", line 102, in __call__
    import pydoc
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pydoc.py", line 66, in <module>
    import platform
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/platform.py", line 116, in <module>
    import sys, os, re, subprocess
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/subprocess.py", line 139, in <module>
    import _posixsubprocess
ImportError: dlopen(/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_posixsubprocess.so, 2): Symbol not found: _PyString_AsString
  Referenced from: /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_posixsubprocess.so
  Expected in: flat namespace
 in /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/_posixsubprocess.so