code: def _convert_trigger(self, trigger_def, parent):
          
  
          if trigger_def.explicit_stream is None:
              stream = parent.resolve_identifier(trigger_def.named_event, DataStream)
              trigger = TrueTrigger()
          else:
              stream = trigger_def.explicit_stream
              trigger = trigger_def.explicit_trigger
  
          return (stream, trigger)
docs: Convert a TriggerDefinition into a stream, trigger pair.