docs: def dag(self) -> Tuple[Dict, Dict]:
          """Construct the DAG of this pipeline based on the its operations and their downstream."""
          from pipelines import dags
  
          operations = self.operations.all().prefetch_related('downstream_operations')
  
          def get_downstream(op):
              return op.downstream_operations.values_list('id', flat=True)
  
          return dags.get_dag(operations, get_downstream)