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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def DeleteOldFeedItems(client, feed_item_ids, feed):
 """Deletes the old feed items for which extension settings have been created. Args: client: an AdWordsClient instance. feed_item_ids: a list of Feed Item Ids. feed: the Feed containing the given Feed Item Ids. """

  if not feed_item_ids:
    return

  feed_item_service = client.GetService('FeedItemService', 'v201809')

  operations = [{
      'operator': 'REMOVE',
      'operand': {
          'feedId': feed['id'],
          'feedItemId': feed_item_id
      }
  } for feed_item_id in feed_item_ids]

  feed_item_service.mutate(operations)