class_docstr: Ranking loss key strings.
code: def all_keys(cls) -> List[str]:
      return [v for k, v in vars(cls).items() if k.isupper()]
  
imports: from typing import Any, Callable, Dict, List, Mapping, Optional, Sequence, Tuple, Union
  import tensorflow
  from tensorflow_ranking.python import losses_impl
  from tensorflow_ranking.python import utils
label_desc: Use image node_id 1 for calling the RankingLossKey obj's underlying member method code with example usage: obj.all_keys(cls) and returns: unknown