class_docstr: Example for a callable class specifyable in yaml files as `policy_mapping_fn`.
code: def __call__(self, agent_id, episode, worker, **kwargs):
      return "p_" + (
          str("0" if int(agent_id.split("_")[-1]) % 2 == 0 else "1")
          if (episode.episode_id) % 2 == 0
          else str(
              "1" if int(agent_id.split("_")[-1]) % 2 == 0 else "0"
          )
      )
  
file_path: ray/rllib_contrib/leela_chess_zero/examples/custom_model.py
imports: import torch.nn
  from ray.rllib.algorithms.alpha_zero.models.custom_torch_models import ActorCriticModel, Flatten
label_desc: Use image node_id 1 for calling the PolicyMappingFn obj's underlying member method code with example usage: obj.__call__(agent_id, episode, worker) and returns: unknown