def METHOD_NAME(utask_module, serialized_uworker_input):
  """Exectues the main part of a utask on the uworker (locally if not using
  remote executor)."""
  logs.log('Starting utask_main: %s.' % utask_module)
  uworker_input = uworker_io.deserialize_uworker_input(serialized_uworker_input)
  # Deal with the environment.
  set_uworker_env(uworker_input.uworker_env)  # pylint: disable=no-member
  delattr(uworker_input, 'uworker_env')
  uworker_output = utask_module.utask_main(uworker_input)
  if uworker_output is None:
    return None
  return uworker_io.serialize_uworker_output(uworker_output)