python 3.4 attempting to run example at https://docs.python.org/3/library/concurrent.futures.html
17.4.2.1

$ python3 17_4_2.py 
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 2195, in _find_and_load_unlocked
AttributeError: 'module' object has no attribute '__path__'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "17_4_2.py", line 1, in <module>
    import concurrent.futures
ImportError: No module named 'concurrent.futures'; 'concurrent' is not a package

os: OS X 10.6

from $env:
PATH=/Library/Frameworks/Python.framework/Versions/3.4/bin:/Library/Frameworks/Python.framework/Versions/2.7/bin: ...

PYTHONPATH=/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/:/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/: ...