text: #!/usr/bin/env python
  #
  # Licensed to the Apache Software Foundation (ASF) under one
  # or more contributor license agreements.  See the NOTICE file
  # distributed with this work for additional information
  # regarding copyright ownership.  The ASF licenses this file
  # to you under the Apache License, Version 2.0 (the
  # "License"); you may not use this file except in compliance
  # with the License.  You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
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  # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, either express or implied.  See the License for the
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  # under the License.
  """Renderer DAG (tasks and dependencies) to the graphviz object."""
  from typing import List, Optional
  
  import graphviz
  
  from airflow.models import TaskInstance
  from airflow.models.dag import DAG
  from airflow.utils.state import State
  
  
  def _refine_color(color: str):
      """
      Converts color in #RGB (12 bits) format to #RRGGBB (32 bits), if it possible.
      Otherwise, it returns the original value. Graphviz does not support colors in #RGB format.
  
      :param color: Text representation of color
      :return: Refined representation of color
      """
      if len(color) == 4 and color[0] == "#":
          color_r = color[1]
          color_g = color[2]
          color_b = color[3]
          return "#" + color_r + color_r + color_g + color_g + color_b + color_b
      return color
  
  
  def render_dag(dag: DAG, tis: Optional[List[TaskInstance]] = None) -> graphviz.Digraph:
      """
      Renders the DAG object to the DOT object.
  
      If an task instance list is passed, the nodes will be painted according to task statuses.
  
      :param dag: DAG that will be rendered.
      :type dag: airflow.models.dag.DAG
      :param tis: List of task instances
      :type tis: Optional[List[TaskInstance]]
      :return: Graphviz object
      :rtype: graphviz.Digraph
      """
      dot = graphviz.Digraph(
          dag.dag_id,
          graph_attr={
              "rankdir": dag.orientation if dag.orientation else "LR",
              "labelloc": "t",
              "label": dag.dag_id,
          },
      )
      states_by_task_id = None
      if tis is not None:
          states_by_task_id = {ti.task_id: ti.state for ti in tis}
      for task in dag.tasks:
          node_attrs = {
              "shape": "rectangle",
              "style": "filled,rounded",
          }
          if states_by_task_id is None:
              node_attrs.update(
                  {
                      "color": _refine_color(task.ui_fgcolor),
                      "fillcolor": _refine_color(task.ui_color),
                  }
              )
          else:
              state = states_by_task_id.get(task.task_id, State.NONE)
              node_attrs.update(
                  {
                      "color": State.color_fg(state),
                      "fillcolor": State.color(state),
                  }
              )
          dot.node(
              task.task_id,
              _attributes=node_attrs,
          )
          for downstream_task_id in task.downstream_task_ids:
              dot.edge(task.task_id, downstream_task_id)
      return dot
  