def METHOD_NAME(self, system, time, current_step: int):
    if current_step % self.every == 0:
        self.callback_params["time"].append(time)
        # Collect only x
        self.callback_params["position"].append(system.position_collection.copy())
        self.callback_params["com"].append(system.compute_position_center_of_mass())
        return