How to use the libmozevent.bus.MessageBus function in libmozevent

def __init__(self, cache_root):
        # Create message bus shared amongst processes
        self.bus = MessageBus()

        publish = taskcluster_config.secrets["PHABRICATOR"].get("publish", False)

        # Check the redis support is enabled on Heroku
        if heroku.in_dyno():
            assert self.bus.redis_enabled is True, "Need Redis on Heroku"

        community_config = taskcluster_config.secrets.get("taskcluster_community")
        test_selection_enabled = taskcluster_config.secrets.get(
            "test_selection_enabled", False
        )

        # Run webserver & pulse on web dyno or single instance
        if not heroku.in_dyno() or heroku.in_web_dyno():

            # Create web server