new_contents: # Copyright 2019 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
  #
  #     https://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.
  """Demonstrates how to create a sitelink extension."""
  
  from __future__ import absolute_import
  
  import argparse
  import six
  import sys
  
  from google.ads.google_ads.client import GoogleAdsClient
  from google.ads.google_ads.errors import GoogleAdsException
  
  
  def main(client, customer_id):
      # Create an extension setting.
      feed_service = client.get_service('ExtensionFeedItemService', version='v1')
  
      extension_feed_item_operation = client.get_type('ExtensionFeedItemOperation', version='v1')
      extension_feed_item = extension_feed_item_operation.create
      extension_feed_item.sitelink_feed_item.link_text.value = 'Text'
      extension_feed_item.sitelink_feed_item.line1.value = 'Line 1 Value'
      extension_feed_item.sitelink_feed_item.line2.value = 'Line 2 Value'
      final_url = extension_feed_item.sitelink_feed_item.final_urls.add()
      final_url.value = 'www.example.com'
  
      # Add extension
      try:
          feed_response = (
              feed_service.mutate_extension_feed_items(customer_id, [extension_feed_item_operation])
          )
      except GoogleAdsException as ex:
          print('Request with ID "%s" failed with status "%s" and includes the '
                'following errors:' % (ex.request_id, ex.error.code().name))
          for error in ex.failure.errors:
              print('\tError with message "%s".' % error.message)
              if error.location:
                  for field_path_element in error.location.field_path_elements:
                      print('\t\tOn field: %s' % field_path_element.field_name)
          sys.exit(1)
  
      print('Created Sitelink %s.' % feed_response.results[0].resource_name)
  
  
  if __name__ == '__main__':
      # GoogleAdsClient will read the google-ads.yaml configuration file in the
      # home directory if none is specified.
      google_ads_client = GoogleAdsClient.load_from_storage()
  
      parser = argparse.ArgumentParser(
          description='Creates sitelink for the specified customer id')
      # The following argument(s) should be provided to run the example.
      parser.add_argument('-c', '--customer_id', type=six.text_type,
                          required=True, help='The Google Ads customer ID')
      args = parser.parse_args()
  
      main(google_ads_client, args.customer_id)
subject: Add add_sitelink example (#59)