Using --save_main_session fails on Python 3 when main module has invocations of superclass method using 'super' .

Traceback (most recent call last):
  File "/usr/lib/python3.5/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.5/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/local/google/home/valentyn/tmp/r2.14.0_py3.5_env/lib/python3.5/site-packages/apache_beam/examples/complete/game/user_score.py", line 164, in <module>                                                
    run()
  File "/usr/local/google/home/valentyn/tmp/r2.14.0_py3.5_env/lib/python3.5/site-packages/apache_beam/examples/complete/game/user_score.py", line 158, in run                                                     
    | 'WriteUserScoreSums' >> beam.io.WriteToText(args.output))
  File "/usr/local/google/home/valentyn/tmp/r2.14.0_py3.5_env/lib/python3.5/site-packages/apache_beam/pipeline.py", line 426, in __exit__                                                                         
    self.run().wait_until_finish()
  File "/usr/local/google/home/valentyn/tmp/r2.14.0_py3.5_env/lib/python3.5/site-packages/apache_beam/runners/dataflow/dataflow_runner.py", line 1338, in wait_until_finish                                       
    (self.state, getattr(self._runner, 'last_error_msg', None)), self)
apache_beam.runners.dataflow.dataflow_runner.DataflowRuntimeException: Dataflow pipeline failed. State: FAILED, Error:                                                                                            
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/site-packages/dataflow_worker/batchworker.py", line 773, in run
    self._load_main_session(self.local_staging_directory)
  File "/usr/local/lib/python3.5/site-packages/dataflow_worker/batchworker.py", line 489, in _load_main_session                                                                                                   
    pickler.load_session(session_file)
  File "/usr/local/lib/python3.5/site-packages/apache_beam/internal/pickler.py", line 280, in load_session                                                                                                        
    return dill.load_session(file_path)
  File "/usr/local/lib/python3.5/site-packages/dill/_dill.py", line 410, in load_session
    module = unpickler.load()
  File "/usr/local/lib/python3.5/site-packages/dill/_dill.py", line 474, in find_class
    return StockUnpickler.find_class(self, module, name)
AttributeError: Can't get attribute 'ParseGameEventFn' on <module 'dataflow_worker.start' from '/usr/local/lib/python3.5/site-packages/dataflow_worker/start.py'>