def _check_sleep(self, idx):
        """This ensures that the robot code called Wait() at some point"""

        # TODO: There are some cases where it would be ok to do this...
        if not self.fake_time.slept[idx]:
            errstr = (
                "%s() function is not calling wpilib.Timer.delay() in its loop!"
                % self.mode_map[self.mode]
            )
            raise RuntimeError(errstr)

        self.fake_time.slept[idx] = False