code: def _CreateFeedMapping(client, feed_details):
    
    # Get the FeedMappingService.
    feed_mapping_service = client.GetService('FeedMappingService',
                                             version='v201809')
  
    # Create the operation.
    operation = {
        # Create the feed mapping.
        'operand': {
            'criterionType': DSA_PAGE_FEED_CRITERION_TYPE,
            'feedId': feed_details.feed_id,
            # Map the feedAttributeIds to the fieldId constants.
            'attributeFieldMappings': [
                {
                    'feedAttributeId': feed_details.url_attribute_id,
                    'fieldId': DSA_PAGE_URLS_FIELD_ID
                },
                {
                    'feedAttributeId': feed_details.label_attribute_id,
                    'fieldId': DSA_LABEL_FIELD_ID
                }
            ]
        },
        'operator': 'ADD'
    }
  
    # Add the feed mapping.
    feed_mapping_service.mutate([operation])
docs: Creates the feed mapping for DSA page feeds.
  
    Args:
      client: an AdWordsClient instance.
      feed_details: a _DSAFeedDetails instance.