new_contents: #!/usr/bin/env python
  # Copyright 2020 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.
  """Links the specified feed item set to the specified feed item.
  
  The specified feed item set must not be created as a dynamic set, i.e. both
  dynamic_location_set_filter and dynamic_affiliate_location_set_filter must not
  be set. Learn more here:
  https://developers.google.com/google-ads/api/docs/location-extensions/feed-item-set?hl=en#adding-feed-item
  """
  
  import argparse
  import sys
  
  from google.ads.google_ads.client import GoogleAdsClient
  from google.ads.google_ads.errors import GoogleAdsException
  from google.ads.google_ads.util import ResourceName
  
  
  def main(client, customer_id, feed_id, feed_item_id, feed_item_set_id):
      """The main method that creates all necessary entities for the example.
  
      Args:
          client: an initialized GoogleAdsClient instance.
          customer_id: a client customer ID.
          feed_id: the ID of the feed associated with the specified feed item set.
          feed_item_id: the ID of the specified feed item.
          feed_item_set_id: the ID of the feed item set to link to the feed item.
      """
      feed_item_set_link_service = client.get_service(
          "FeedItemSetLinkService", version="v6"
      )
      feed_item_set_link_operation = client.get_type(
          "FeedItemSetLinkOperation", version="v6"
      )
  
      # Construct an operation that will link the feed item to the feed item set.
      feed_item_set_link = feed_item_set_link_operation.create
  
      # Construct a resource name for a feed item, which is in the format:
      # customers/{customer_id}/feedItems/{feed_id}~{feed_item_id}
      feed_item_set_link.feed_item = client.get_service(
          "FeedItemService", version="v6"
      ).feed_item_path(
          customer_id, ResourceName.format_composite(feed_id, feed_item_id),
      )
      # Construct a resource name for a feed item set, which is in the
      # format: customers/{customer_id}/feedItemSets/{feed_id}~{feed_item_set_id}
      feed_item_set_link.feed_item_set = client.get_service(
          "FeedItemSetService", version="v6"
      ).feed_item_set_path(
          customer_id, ResourceName.format_composite(feed_id, feed_item_set_id),
      )
  
      # Issue a mutate request to add the feed item set link on the server.
      try:
          response = feed_item_set_link_service.mutate_feed_item_set_links(
              customer_id, [feed_item_set_link_operation]
          )
          print(
              "Created a feed item set link with resource name: "
              f"'{response.results[0].resource_name}'"
          )
      except GoogleAdsException as ex:
          print(
              f'Request with ID "{ex.request_id}" failed with status '
              f'"{ex.error.code().name}" and includes the following errors:'
          )
          for error in ex.failure.errors:
              print(f'\tError with message "{error.message}".')
              if error.location:
                  for field_path_element in error.location.field_path_elements:
                      print(f"\t\tOn field: {field_path_element.field_name}")
          sys.exit(1)
  
  
  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=
              "Links the specified feed item set to the specified feed item."
      )
      # The following argument(s) should be provided to run the example.
      parser.add_argument(
          "-c",
          "--customer_id",
          type=str,
          required=True,
          help="The Google Ads customer ID.",
      )
      parser.add_argument(
          "-f",
          "--feed_id",
          type=str,
          required=True,
          help="The feed ID.",
      )
      parser.add_argument(
          "-i",
          "--feed_item_id",
          type=str,
          required=True,
          help="The feed item ID.",
      )
      parser.add_argument(
          "-s",
          "--feed_item_set_id",
          type=str,
          required=True,
          help="The feed item set ID.",
      )
      args = parser.parse_args()
  
      main(
          google_ads_client,
          args.customer_id,
          args.feed_id,
          args.feed_item_id,
          args.feed_item_set_id,
      )
  
subject: Add link_feed_item_set example (#352)