code: def is_instance_throughput_too_low(self, inst_id):
          
          r = self.instance_throughput_ratio(inst_id)
          if r is None:
              logger.debug("{} instance {} throughput is not "
                           "measurable.".format(self, inst_id))
              return None
          too_low = r < self.Delta
          if too_low:
              logger.display("{}{} instance {} throughput ratio {} is lower than Delta {}.".
                             format(MONITORING_PREFIX, self, inst_id, r, self.Delta))
          else:
              logger.trace("{} instance {} throughput ratio {} is acceptable.".
                           format(self, inst_id, r))
          return too_low
docs: Return whether the throughput of the master instance is greater than the
          acceptable threshold