def reset(self, env, vehicle=None):
        """
        Clear stack
        :param env: MetaDrive
        :param vehicle: BaseVehicle
        :return: None
        """
        self.state = np.zeros(self.observation_space.shape, dtype=np.float32)
        if self.enable_cuda:
            self.state = cp.asarray(self.state)

        Clear stack
        :param env: MetaDrive
        :param vehicle: BaseVehicle
        :return: None
        
metadrive/obs/image_obs.py