def GetParentFileEntry(self):
    """Retrieves the parent file entry.

    Returns:
      APFSFileEntry: parent file entry or None if not available.
    """
    parent_location = None

    location = getattr(self.path_spec, 'location', None)
    if location is not None:
      parent_location = self._file_system.DirnamePath(location)
      if parent_location == '':
        parent_location = self._file_system.PATH_SEPARATOR

    parent_identifier = self._fsapfs_file_entry.parent_identifier
    if parent_identifier is None:
      return None

    parent_path_spec = getattr(self.path_spec, 'parent', None)
    path_spec = apfs_path_spec.APFSPathSpec(
        location=parent_location, identifier=parent_identifier,
        parent=parent_path_spec)

    is_root = bool(
        parent_location == self._file_system.LOCATION_ROOT or
        parent_identifier == self._file_system.ROOT_DIRECTORY_IDENTIFIER)

    return APFSFileEntry(
        self._resolver_context, self._file_system, path_spec, is_root=is_root)
Retrieves the parent file entry.

    Returns:
      APFSFileEntry: parent file entry or None if not available.