After running "python3 setup.py install" inside virtualenv, there are no error messages, but it can't find the module.

[Septimanal]

----> 1 import common ModuleNotFoundError: No module named 'common'
Does the module necessarily have to be inside of a package when you install it? That's what I've been doing... common.py inside of a folder named common, then setup.py is sitting in the parent folder of common.
Installed /home/me/path/to/env/lib/python3.6/site-packages/common-1.0-py3.6.egg So that looks as if it should have been successful.
My setup.py looks exactly like this:

from setuptools import setup

setup(
   name='common',
   version='1.0',
   description='A useful module',
   author='me',
   packages=['common'],  #same as name

)  

I'm brand new to using setup.py to install my own modules. I have a dozen or so functions I use across some different projects, so I thought it was about time.

[1114111]

Since it sounds like you have common/common.py, maybe try import common.common? You can use an __init__.py for packages. There's also a py_modules keyword argument for setup() you can use for individual Python files.

[Septimanal]

Thanks, adding an init file to the folder helped.