def getManager(self, force=False):
        """Extract the YadisServiceManager for this object's URL and
        suffix from the session.

        @param force: True if the manager should be returned
        regardless of whether it's a manager for self.url.

        @return: The current YadisServiceManager, if it's for this
            URL, or else None
        """
        manager = self.session.get(self.getSessionKey())
        if (manager is not None and (manager.forURL(self.url) or force)):
            return manager
        else:
            return None
Extract the YadisServiceManager for this object's URL and
        suffix from the session.

        @param force: True if the manager should be returned
        regardless of whether it's a manager for self.url.

        @return: The current YadisServiceManager, if it's for this
            URL, or else None