def _GetSubFileEntries(self):
    """Retrieves sub file entries.

    Yields:
      TSKFileEntry: a sub file entry.
    """
    if self._directory is None:
      self._directory = self._GetDirectory()

    if self._directory:
      for path_spec in self._directory.entries:
        yield TSKFileEntry(self._resolver_context, self._file_system, path_spec)
Retrieves sub file entries.

    Yields:
      TSKFileEntry: a sub file entry.