Subclass `pathlib.Path` fails

You can subclass the concrete implementation, so this works:

class Path(type(pathlib.Path())):

Here’s what I did with this:

import pathlib

class Path(type(pathlib.Path())):
    def open(self, mode="r", buffering=-1, encoding=None, errors=None, newline=None):
        if encoding is None and 'b' not in mode:
            encoding = 'utf-8'
        return super().open(mode, buffering, encoding, errors, newline)

Path('/tmp/a.txt').write_text("я")