Accessing a field from the class is not yet supported #12

Currently PyCharm has an issue with type hints when the __get__ descriptor returns self for class access. See https://youtrack.jetbrains.com/issue/PY-38151

So this behaviour is currently disabled and replaced with an exception (raise ClassFieldAccessError). We should put it back when it is fixed on pycharm.

For example see https://github.com/smarie/python-pyfields/blob/master/pyfields/core.py#L800