Get the requested intervals (from the database)

        :return: The requested intervals

def requested_intervals(self):
        """
        Get the requested intervals (from the database)

        :return: The requested intervals
        """
        with switch_db(WorkflowStatusModel, db_alias='hyperstream'):
            workflow_statuses = WorkflowStatusModel.objects(workflow_id=self.workflow_id)
            if len(workflow_statuses) == 1:
                return TimeIntervals(map(lambda x: TimeInterval(x.start, x.end),
                                         workflow_statuses[0].requested_intervals))
            else:
                return TimeIntervals([])