'sys.path' must not include foreign paths

[tmontes]

CURRENT macOS FACT:

• Packaged Mu with Python 3.7.
• Checked the value of the bundled Python environment's sys.path with:

$ ./build/pup/mu-editor.app/Contents/Resources/Python/bin/python3 -q
>>> import sys
>>> print(*map(repr, sys.path), sep='\n')
''
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python37.zip'
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python3.7'
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python3.7/lib-dynload'
'${HOME}/.local/lib/python3.7/site-packages'
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python3.7/site-packages'
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python3.7/site-packages/setuptools-49.6.0-py3.7.egg'
'${PWD}/build/pup/mu-editor.app/Contents/Resources/Python/lib/python3.7/site-packages/pip-20.2.2-py3.7.egg'
>>> 

NEEDS CHANGE:

• Two entries should be eliminated from sys.path:
  • The '' empty one, corresponding to the current working directory.
  • The ${HOME}/.local/lib/python3.7/site-packages which, I suppose, holds pip --user installed packages.

WONDERING:

• What kind of sys.path values are we getting on Windows?
• What about Python 3.8 variations?

RELATED:

• This BeeWare briefcase issue, in particular from this comment onwards. :-)

[tmontes]

CLOSING:

• Same as Launch the Python interpreter using the -I flag #195.