code: def update(self, sha, force=False):
          
          data = {'sha': sha, 'force': force}
          json = self._json(self._patch(self._api, data=dumps(data)), 200)
          if json:
              self._update_(json)
              return True
          return False
docs: Update this reference.
  
          :param str sha: (required), sha of the reference
          :param bool force: (optional), force the update or not
          :returns: bool