code: def _finalize_step(self):
          
          t = time.time()
          if self._callback is not None:
              self._callback(self.age)
          t2 = time.time()
          self._step_processing_time += t2 - t
          self._log(logging.INFO, "Step {} run in: {:.3f}s ({:.3f}s of "
                    "actual processing time used)"
                    .format(self.age, self._step_processing_time,
                            t2 - self._step_start_time))
          self._processing_time += self._step_processing_time
docs: Finalize simulation step after all agents have acted for the current
          step.