Importing numpy leads to ModuleNotFoundError

[SeRealMF]

When executing npz.py in splinepy/io a ModuleNotFoundError will be raised.

This is because of the following line of code:
import numpy as np

Numpy is using json but because of the fact that json.py is another file in the splinepy/io folder, it will therefore execute this file instead.
This leads to the following error message:

Traceback (most recent call last):
  File "...\splinepy\splinepy\io\npz.py", line 11, in <module>
    import numpy as np
  File "...\AppData\Local\python\mu\mu_venv-38-20221219-011508\lib\site-packages\numpy\__init__.py", line 140, in <module>
    from . import core
  File "...\AppData\Local\python\mu\mu_venv-38-20221219-011508\lib\site-packages\numpy\core\__init__.py", line 9, in <module>
    from numpy.version import version as __version__
  File "...\AppData\Local\python\mu\mu_venv-38-20221219-011508\lib\site-packages\numpy\version.py", line 3, in <module>
    from ._version import get_versions
  File "...\AppData\Local\python\mu\mu_venv-38-20221219-011508\lib\site-packages\numpy\_version.py", line 7, in <module>
    import json
  File "...\splinepy\splinepy\io\json.py", line 10, in <module>
    from splinepy import settings
ModuleNotFoundError: No module named 'splinepy'

[j042]

This is very rare use-case. In general, I'd like to add leading underscore to module local imports, then these things shouldn't happen.

[clemens-fricke]

I was not able to reproduce this error at all. Even with a completely clean environment.

[SeRealMF]

I was successfully able to reproduce the error, though only on Windows, not on Linux. There may also be many other factors that influence whether the error appears or not.

[j042]

This is very rare use-case. In general, I'd like to add leading underscore to module local imports, then these things shouldn't happen.

Would still happen with json as it has the same name as built-in module. For this one, we will have to add a trailing underscore. You can add this to #296.

[clemens-fricke]

After merging #309, does this issue persist? Could you check this @SeRealMF and close this issue if the problem is fixed?

[SeRealMF]

The issue still persists, even with the latest changes. @j042 mentioned a trailing underscore, though the issue seems resolved in my opinion with a leading underscore of json.py. No errors occur when the file is named _json.py.
Again, in my case all those notes apply only to Windows. No problems on Linux.