Missing type exports for vendored `py`

I want to report a side effect of this change when using mypy. py used to be typed, while apparently the vendored library is not. Downstream developers that define pytest hooks may now see mypy errors like:

nbvalx/pytest_hooks_notebooks.py:32: error: Skipping analyzing "py": module is
installed, but missing library stubs or py.typed marker  [import]
    import py
    ^
nbvalx/pytest_hooks_notebooks.py:32: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
nbvalx/pytest_hooks_notebooks.py:412: error: Argument 2 to "collect_file"
becomes "Any" due to an unfollowed import  [no-any-unimported]
    def collect_file(file_path: pathlib.Path, path: py.path.local, parent:...
    ^

I'll leave it to you to decide if it is worth it to add back that support (downstream developers can easily add a couple of ignores, especially knowing that py.path is being deprecated anyway), but I want to report this here for future reference because at the beginning I couldn't wrap my head around what had happened (latest py release was one year ago, and surely I had ran my CI last week without errors) and it took me a while to figure out what was going on.

Cheers,
Francesco

Originally posted by @francesco-ballarin in https://github.com/pytest-dev/pytest/issues/10396#issuecomment-1291525602

Start by reproducing the mypy run against nbvalx/pytest_hooks_notebooks.py, especially lines 32 and 412, and inspect the change that replaced the typed py dependency with the vendored library. Done means the supported approach for pytest hook users is established and the reported missing-stub and Any errors are resolved or explicitly documented.