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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _locked_tmp_dir_size(lock_filename):
 """Returns the size of the temp dir pointed to by the given lock file."""

  task_uid = _task_uid_from_lock_file(lock_filename)
  try:
    return _dir_size(
        _temp_download_dir(_module_dir(lock_filename), task_uid))
  except tf.errors.NotFoundError:
    return 0