Returns the coordinator broker for a consumer group.

        GroupCoordinatorNotAvailableError will be raised if the coordinator
        does not currently exist for the group.

        GroupLoadInProgressError is raised if the coordinator is available
        but is still loading offsets from the internal topic

def _get_coordinator_for_group(self, group):
        """
        Returns the coordinator broker for a consumer group.

        GroupCoordinatorNotAvailableError will be raised if the coordinator
        does not currently exist for the group.

        GroupLoadInProgressError is raised if the coordinator is available
        but is still loading offsets from the internal topic
        """

        resp = self.send_consumer_metadata_request(group)

        # If there's a problem with finding the coordinator, raise the
        # provided error
        kafka.errors.check_error(resp)

        # Otherwise return the BrokerMetadata
        return BrokerMetadata(resp.nodeId, resp.host, resp.port, None)