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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _fetch_atari_metrics(base_env):
 """Atari games have multiple logical episodes, one per life. However for metrics reporting we count full episodes all lives included. """

    unwrapped = base_env.get_unwrapped()
    if not unwrapped:
        return None
    atari_out = []
    for u in unwrapped:
        monitor = get_wrapper_by_cls(u, MonitorEnv)
        if not monitor:
            return None
        for eps_rew, eps_len in monitor.next_episode_results():
            atari_out.append(RolloutMetrics(eps_len, eps_rew, {}, {}, {}))
    return atari_out