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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 on_episode_begin(self, episode, logs):
 """ Reset environment variables at beginning of each episode """

        self.episode_start[episode] = timeit.default_timer()
        self.observations[episode] = []
        self.rewards[episode] = []
        self.actions[episode] = []
        self.metrics[episode] = []