ray/rllib/evaluation/rollout_metrics.py

import collections

# Define this in its own file, see #5125
RolloutMetrics = collections.namedtuple("RolloutMetrics", [
    "episode_length", "episode_reward", "agent_rewards", "custom_metrics",
    "perf_stats", "hist_data"
])
RolloutMetrics.__new__.__defaults__ = (0, 0, {}, {}, {}, {})