code: def GetCampaignFeeds(client, feed, placeholder_type):
    
    campaign_feed_service = client.GetService('CampaignFeedService', 'v201809')
  
    campaign_feeds = []
    more_pages = True
  
    selector = {
        'fields': ['CampaignId', 'MatchingFunction', 'PlaceholderTypes'],
        'predicates': [
            {
                'field': 'Status',
                'operator': 'EQUALS',
                'values': ['ENABLED']
            },
            {
                'field': 'FeedId',
                'operator': 'EQUALS',
                'values': [feed['id']]
            },
            {
                'field': 'PlaceholderTypes',
                'operator': 'CONTAINS_ANY',
                'values': [placeholder_type]
            }
        ],
        'paging': {
            'startIndex': 0,
            'numberResults': PAGE_SIZE
        }
    }
  
    while more_pages:
      page = campaign_feed_service.get(selector)
  
      if 'entries' in page:
        campaign_feeds.extend(page['entries'])
  
      selector['paging']['startIndex'] += PAGE_SIZE
      more_pages = selector['paging']['startIndex'] < int(page['totalNumEntries'])
  
    return campaign_feeds
docs: Get a list of Feed Item Ids used by a campaign via a given Campaign Feed.
  
    Args:
      client: an AdWordsClient instance.
      feed: a Campaign Feed.
      placeholder_type: the Placeholder Type.
  
    Returns:
      A list of Feed Item Ids.