code: def update_limits(self):
          
          if self.limits_updated:
              logger.debug('Already polled TA; skipping update')
              return
          self.connect()
          ta_results = self._poll()
          self._update_services(ta_results)
          self.limits_updated = True
docs: Poll 'Service Limits' check results from Trusted Advisor, if possible.
          Iterate over all :py:class:`~.AwsLimit` objects for the given services
          and update their limits from TA if present in TA checks.
  
          :param services: dict of service name (string) to
            :py:class:`~._AwsService` objects
          :type services: dict