The _path_is_dir function in file system notifications on windows is broken

The function _path_is_dir does not work as expected, the following implementation is wrong:

    @is_valid_windows_path(path_indexes=[1])
    def _path_is_dir(self, path):
        """Check if the path is a dir and update the local subdir list."""
        self.log.debug('Testing if path %r is a dir', path)
        is_dir = False
        if os.path.exists(path):
            is_dir = os.path.isdir(path)
        else:
            self.log.debug('Path "%s" was deleted subdirs are %s.',
                path, self._subdirs)
            # we removed the path, we look in the internal list
            if path in self._subdirs:
                is_dir = True
                self._subdirs.remove(path)
        if is_dir:
            self.log.debug('Adding %s to subdirs %s', path, self._subdirs)
            self._subdirs.append(path)
        return is_dir

This can brake terribly.