How to run matplotlib in a clone project?


I have cloned Matplotlib from github in order to make changes and submit them after in a pull request.
Before pulling, I would like to test my changes with a local test I made.
When running it, I have the following error message :

import matplotlib.pyplot as plt

from matplotlib import _api, _c_internal_utils
ImportError: cannot import name ‘_c_internal_utils’ from ‘matplotlib’ …

_c_internal_utils is a C library that I have found in src/tri.

So basically, How to run a test inside a (Pycharm) matplotlib project issued from a github clone ?
Thanks for your help,

Please see directions in Setting up Matplotlib for development — Matplotlib 3.5.1 documentation for how to set up an “editable install”. You need get the c-extensions compiled for Matplotlib to work!