Python 2.7 compatibility

[tbrx]

I believe we should still be supporting python 2.7 with the distributions code (as well as 3.x). The pre-existing distributions-api branch includes some code which doesn't parse on 2.7.

My understanding is that pytorch in general targets 2.7 and 3.5+ — is this correct?

[neerajprad]

That is correct - PyTorch (and Pyro, as well) supports both 2.7 and 3.5+. We used the six library to handle imports of common library functions. PyTorch seems to have an internal _six file to specify the appropriate python 2/3 packages to bind to the namespace depending on the runtime python version.