Pip install fails on Python>=3.7

[aalok-sathe]

Haven't been able to pip install on python3.7 or python3.8.
Perhaps setup.py needs cython in the requirements list?

Cloning the repo and manually doing a pip install . worked, once I installed cython separately.

[stephanie-flower]

Having a similar issue (Python 3.9) but pip install . doesn't seem to be working at all.