code: def ids(self, content_ids, object_ids):
          
          result = []
  
          content_ids = self.split(content_ids, False)
          object_ids = self.split(object_ids)
  
          for cid in content_ids:
              result.append('{}:{}'.format(cid, ':'.join(object_ids)))
  
          return result
docs: Appends the content and object ids how RETS expects them