checkpoint, please change your optimizer to
        `tf.keras.optimizers.legacy.XXX` (e.g.
        `tf.keras.optimizers.legacy.Adam`).
    *   **TF1 compatibility.** The new optimizer does not support TF1 any more,
        so please use the legacy optimizer `tf.keras.optimizer.legacy.XXX`.
        We highly recommend to migrate your workflow to TF2 for stable
        support and new features.

  environ_cp[var_name] = str(var)


def convert_version_to_int(version):
  """Convert a version number to a integer that can be used to compare.

  Version strings of the form X.YZ and X.Y.Z-xxxxx are supported. The
  'xxxxx' part, for instance 'homebrew' on OS/X, is ignored.

  Args:
    version: a version to be converted

  Returns:
    An integer if converted successfully, otherwise return None.
  """