How to use the mechanicalsoup.__version__.__version__ function in MechanicalSoup

def set_user_agent(self, user_agent):
        """Replaces the current user agent in the requests session headers."""
        # set a default user_agent if not specified
        if user_agent is None:
            requests_ua = requests.utils.default_user_agent()
            user_agent = '%s (%s/%s)' % (requests_ua, __title__, __version__)

        # the requests module uses a case-insensitive dict for session headers
        self.session.headers['User-agent'] = user_agent