code: def dag(self) -> Tuple[Dict, Dict]:
          
          from pipelines import dags
  
          operation_runs = self.operation_runs.all().prefetch_related('downstream_runs')
  
          def get_downstream(op_run):
              return op_run.downstream_runs.values_list('id', flat=True)
  
          return dags.get_dag(operation_runs, get_downstream)
docs: Construct the DAG of this pipeline run
          based on the its operation runs and their downstream.