ImportError: No module named atari_py

Hi there,

When I try to run "python tests/atari_init_test.py", the following error message appears:
ImportError: No module named atari_py

However, atari_py was installed using pip install atari-py, and when try again installing atari-py, it indicates: requirement already satisfied: atari_py in /usr/local/lib/python2.7/dist-packages

System environment information are:
Ubuntu 16.04;
Python: 2.7/15 | Anaconda, Inc. | default, May 1 2018

Any way to help locate atari_py?

Cheers,