Resets the environment.

        Returns:
            A Data structure corresponding to the initial reset state of the
            environment.

def _reset_env(self, env: BaseUnityEnvironment):
        """Resets the environment.

        Returns:
            A Data structure corresponding to the initial reset state of the
            environment.
        """
        if self.meta_curriculum is not None:
            return env.reset(train_mode=self.fast_simulation, config=self.meta_curriculum.get_config())
        else:
            return env.reset(train_mode=self.fast_simulation)