code: def get_learning_rate(self, iter):
      return self.init_lr * (
          (math.cos(iter * 1.0 / self.max_iter * math.pi) + 1.0) * 0.5
      )
  
file_path: nnabla/python/test/utils/learning_rate_scheduler/test_cosine_scheduler.py
imports: import pytest
  from learning_rate_scheduler_test_utils import scheduler_tester
  import nnabla.utils.learning_rate_scheduler
  import math
label_desc: Use image node_id 2 for calling the RefCosine obj's underlying member method code with example usage: obj.get_learning_rate(iter) and returns: unknown