code: def committer(cls, config_reader=None):
          
          return cls._main_actor(cls.env_committer_name, cls.env_committer_email, config_reader)
docs: :return: Actor instance corresponding to the configured committer. It behaves
              similar to the git implementation, such that the environment will override
              configuration values of config_reader. If no value is set at all, it will be
              generated
          :param config_reader: ConfigReader to use to retrieve the values from in case
              they are not set in the environment