code: def patch_dag(
      *,
      dag_id: str,
      update_mask: UpdateMask = None,
      session: Session = NEW_SESSION,
  ) -> APIResponse:
      """Update the specific DAG."""
      try:
          patch_body = dag_schema.load(request.json, session=session)
      except ValidationError as err:
          raise BadRequest(detail=str(err.messages))
      if update_mask:
          patch_body_ = {}
          if update_mask != ["is_paused"]:
              raise BadRequest(
                  detail="Only `is_paused` field can be updated through the REST API"
              )
          patch_body_[update_mask[0]] = patch_body[update_mask[0]]
          patch_body = patch_body_
      dag = session.scalar(
          select(DagModel).where(DagModel.dag_id == dag_id)
      )
      if not dag:
          raise NotFound(f"Dag with id: '{dag_id}' not found")
      dag.is_paused = patch_body["is_paused"]
      session.flush()
      return dag_schema.dump(dag)
  
imports: from __future__ import annotations
  from http import HTTPStatus
  from typing import TYPE_CHECKING, Collection
  from connexion import NoContent
  from flask import g, request
  from marshmallow import ValidationError
  from sqlalchemy import select, update
  from sqlalchemy.sql.expression import or_
  from airflow.api_connexion import security
  from airflow.api_connexion.exceptions import AlreadyExists, BadRequest, NotFound
  from airflow.api_connexion.parameters import apply_sorting, check_limit, format_parameters
  from airflow.api_connexion.schemas.dag_schema import DAGCollection, DAGCollectionSchema, DAGDetailSchema, DAGSchema, dag_schema, dags_collection_schema
  from airflow.exceptions import AirflowException, DagNotFound
  from airflow.models.dag import DagModel, DagTag
  from airflow.utils.airflow_flask_app import get_airflow_app
  from airflow.utils.db import get_query_count
  from airflow.utils.session import NEW_SESSION, provide_session
  from airflow.www.extensions.init_auth_manager import get_auth_manager
label_desc: Use image node_id 4 for calling a global function with example usage: patch_dag() and returns: dag_schema