#! /bin/env python3
#

from errno import ENODATA
from pathlib import Path
from os import getxattr, setxattr

class Path_(type(Path())):

    __slots__ = ("_new_attr",)

    def __new__(cls, *args, new_attr=None, **kwargs):
        self = super().__new__(cls, *args, **kwargs)
        self._new_attr = new_attr
        return self

    @property
    def new_attr(self):
        if self._new_attr:
            return self._new_attr

        try:
            new_attr = getxattr(str(self), "user.new_attr")
        except OSError as exc:
            if exc.errno != ENODATA:
                raise exc
        else:
            self._new_attr = new_attr
            return new_attr

        new_attr = b"something" # generate the new_attr
        setxattr(str(self), "user.new_attr", new_attr)
        self._new_attr = new_attr
        return new_attr

#    @classmethod
#    def _from_parsed_parts(cls, drv, root, parts, init=True):
#        self = cls.__new__(cls)
#        self._drv = drv
#        self._root = root
#        self._parts = parts
#        if init:
#            self._init()
#        return self

if __name__ == "__main__":
    print(Path_("reproducer.py").parent.new_attr)