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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 instantiate_single(self, seed=0, preset='default'):
 """ Create a new Env instance - single """

        env = self.env.instantiate(seed=seed, serial_id=0, preset=preset)

        if self.frame_history is not None:
            env = FrameStack(env, self.frame_history)

        return env