def get_checkpoints(self):
        """Return next checkpoint and the next next checkpoint"""
        later_middle = (float(self.get_current_lane_num()) / 2 - 0.5) * self.get_current_lane_width()
        ref_lane1 = self.current_ref_lanes[0]
        checkpoint1 = ref_lane1.position(ref_lane1.length, later_middle)
        ref_lane2 = self.next_ref_lanes[0] if self.next_ref_lanes is not None else self.current_ref_lanes[0]
        checkpoint2 = ref_lane2.position(ref_lane2.length, later_middle)
        return checkpoint1, checkpoint2
Return next checkpoint and the next next checkpoint
metadrive/component/navigation_module/base_navigation.py