> [pathlib] is a good object-oriented solution

I'd agree that pathlib is a good solution, and that it's an object-oriented solution, but I'm hesitant to call it a good object-oriented solution. It uses some object-oriented hackery to work as elegantly as it does. I approve of this decision, but it leads to some weirdness such as the inability to subclass `pathlib.Path`. Instead you need to subclass `type(pathlib.Path())`, as the method resolution order changes once it is instantiated:

    >>> from pathlib import Path
    >>> Path.__mro__
    (<class 'pathlib.Path'>, <class 'pathlib.PurePath'>, <class 'object'>)
    >>> type(Path()).__mro__
    (<class 'pathlib.PosixPath'>, <class 'pathlib.Path'>, <class 'pathlib.PurePosixPath'>, <class 'pathlib.PurePath'>, <class 'object'>)

In any case, weirdness like this can make for an even better learning opportunity!