It is probably a problem with the Python IDE you use. If you use Canopy, make sure you have the eppy package installed in the virtual environment of Canopy. You can check this in Canopy, by opening tools --> Canopy command prompt and typing pip freeze or pip list. If eppy is not listed here, try pip install eppy it in this Canopy command prompt, then restart Canopy.

If this doesn't work, try to search for solution on Stack overflow, as it is more of a programming issue, you can probably find good advice there.