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.discrete_domains import logger
  import mock
  import numpy
  from tensor2tensor.rl import dopamine_connector
  import tensorflow.compat.v1
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