code: def test_build_constant_scheduler(self):
      config = self._get_valid_config()
      scheduler = build_param_scheduler(config)
      self.assertTrue(isinstance(scheduler, ConstantParamScheduler))
  
file_path: ClassyVision/test/optim_param_scheduler_constant_test.py
imports: import copy
  import unittest
  from classy_vision.optim.param_scheduler import build_param_scheduler, ConstantParamScheduler
label_desc: Use image node_id 4 for calling the TestFixedScheduler obj's underlying member method code with example usage: obj.test_build_constant_scheduler() without return types