TypeError when calling files() on a directory without an `__init__.py`
trying to listing a directory without an __init__.py
results in a runtime error:
In [1]: import importlib_resources
In [2]: !mkdir test123
In [3]: importlib_resources.files("test123")
...
TypeError: expected str, bytes or os.PathLike object, not NoneType
Should there be a more specific exception here to allow dependent projects detect this condition and issue a useful message to the end user?