code: def get_learning_rate(self, iter):
      lr = self.init_lr
      for step in self.iter_steps:
          if iter >= step:
              lr *= self.gamma
      return lr
  
file_path: nnabla/python/test/utils/learning_rate_scheduler/test_step_scheduler.py
imports: import pytest
  from learning_rate_scheduler_test_utils import scheduler_tester
  import nnabla.utils.learning_rate_scheduler
label_desc: Use image node_id 2 for calling the RefStep obj's underlying member method code with example usage: obj.get_learning_rate(iter) and returns: lr