code: def get_block_containing_tx(self, txid):
          
          blocks = list(backend.query.get_block_with_transaction(self.connection, txid))
          if len(blocks) > 1:
              logger.critical('Transaction id %s exists in multiple blocks', txid)
  
          return [block['height'] for block in blocks]
docs: Retrieve the list of blocks (block ids) containing a
             transaction with transaction id `txid`
  
          Args:
              txid (str): transaction id of the transaction to query
  
          Returns:
              Block id list (list(int))