class_docstr: Class to mock the experiment logger.
class_docstr_tok: ["Class","to","mock","the","experiment","logger","."]
code: def log_to_file(self, filename_prefix, iteration_number):
      if self._run_asserts:
          self._test_cls.assertEqual(
              "prefix_{}".format(self._iter - 1),
              "{}_{}".format(filename_prefix, iteration_number),
          )
      self._calls_to_log += 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 3 for calling the MockLogger obj's underlying member method code with example usage: obj.log_to_file(filename_prefix, iteration_number) without return types