text: # -*- coding: utf-8 -*-
  #
  # 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
  #
  # Unless required by applicable law or agreed to in writing,
  # software distributed under the License is distributed on an
  # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, either express or implied.  See the License for the
  # specific language governing permissions and limitations
  # under the License.
  
  from typing import Set
  
  
  class TriggerRule:
      ALL_SUCCESS = 'all_success'
      ALL_FAILED = 'all_failed'
      ALL_DONE = 'all_done'
      ONE_SUCCESS = 'one_success'
      ONE_FAILED = 'one_failed'
      NONE_FAILED = 'none_failed'
      NONE_SKIPPED = 'none_skipped'
      DUMMY = 'dummy'
  
      _ALL_TRIGGER_RULES = set()  # type: Set[str]
  
      @classmethod
      def is_valid(cls, trigger_rule):
          return trigger_rule in cls.all_triggers()
  
      @classmethod
      def all_triggers(cls):
          if not cls._ALL_TRIGGER_RULES:
              cls._ALL_TRIGGER_RULES = {
                  getattr(cls, attr)
                  for attr in dir(cls)
                  if not attr.startswith("_") and not callable(getattr(cls, attr))
              }
          return cls._ALL_TRIGGER_RULES
  