code: def _apply_context_mutator(self, mutator_class):
      opt = Opt()
      mutator = mutator_class(opt)
      mutated = mutator(self._setup_data_with_context())
      return list(mutated)
  
imports: import unittest
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.teachers import create_task_agent_from_taskname
  from parlai.core.message import Message
label_desc: Use image node_id 5 for calling the TestSpecificMutators obj's underlying member method code with example usage: obj._apply_context_mutator(mutator_class) and returns: list