docs: def default_metric_definitions(cls, toolkit):
          """Provides default metric definitions based on provided toolkit.
  
          Args:
              toolkit(sagemaker.rl.RLToolkit): RL Toolkit to be used for training.
  
          Returns:
              list: metric definitions
          """
          if toolkit is RLToolkit.COACH:
              return [
                  {'Name': 'reward-training',
                   'Regex': '^Training>.*Total reward=(.*?),'},
                  {'Name': 'reward-testing',
                   'Regex': '^Testing>.*Total reward=(.*?),'}
              ]
          elif toolkit is RLToolkit.RAY:
              float_regex = "[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?"  # noqa: W605, E501 pylint: disable=anomalous-backslash-in-string
              return [
                  {'Name': 'episode_reward_mean',
                   'Regex': 'episode_reward_mean: (%s)' % float_regex},
                  {'Name': 'episode_reward_max',
                   'Regex': 'episode_reward_max: (%s)' % float_regex}
              ]