code: def _create_hparam_extractor(hparam_name):
    
    def extractor_fn(session_group):
      if hparam_name in session_group.hparams:
        return _value_to_python(session_group.hparams[hparam_name])
      return None
  
    return extractor_fn
docs: Returns an extractor function that extracts an hparam from a session group.
  
    Args:
      hparam_name: str. Identies the hparam to extract from the session group.
    Returns:
      A function that takes a tensorboard.hparams.SessionGroup protobuffer and
      returns the value, as a native Python object, of the hparam identified by
      'hparam_name'.