code: def find_usage(self):
          
          logger.debug("Checking usage for service %s", self.service_name)
          self.connect()
          for lim in self.limits.values():
              lim._reset_usage()
          try:
              self._find_usage_filesystems()
          except (EndpointConnectionError, ClientError, ConnectTimeout) as ex:
              logger.warning(
                  'Caught exception when trying to use EFS ('
                  'perhaps the EFS service is not available in this '
                  'region?): %s', ex
              )
          self._have_usage = True
          logger.debug("Done checking usage.")
docs: Determine the current usage for each limit of this service,
          and update corresponding Limit via
          :py:meth:`~.AwsLimit._add_current_usage`.