class_docstr: Class to mock the experiment logger.
class_docstr_tok: ["Class","to","mock","the","experiment","logger","."]
code: def __setitem__(self, key, val):
      if self._run_asserts:
          self._test_cls.assertEqual(
              "iteration_{:d}".format(self._iter), key
          )
          self._test_cls.assertEqual("statistics", val)
          self._iter += 1
      self._calls_to_set += 1
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  from absl import flags
  from dopamine.agents.dqn import dqn_agent
  from dopamine.agents.implicit_quantile import implicit_quantile_agent
  from dopamine.agents.rainbow import rainbow_agent
  from dopamine.discrete_domains import checkpointer
  from dopamine.discrete_domains import logger
  from dopamine.discrete_domains import run_experiment
  from dopamine.metrics import collector_dispatcher
  from dopamine.metrics import statistics_instance
  import gin.tf
  import mock
  import tensorflow
label_desc: Use image node_id 2 for calling the MockLogger obj's underlying member method code with example usage: obj.__setitem__(key, val) without return types