text: # Copyright 2018 Google LLC
  #
  # Licensed 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.
  
  
  # [START functions_env_vars]
  import os
  
  
  def env_vars(request):
      return os.environ.get('FOO', 'Specified environment variable is not set.')
  # [END functions_env_vars]
  