code: def add_option(self, mask):
          
          if not isinstance(mask, int):
              raise TypeError("mask must be an int")
          self.__check_okay_to_chain()
  
          if mask & _QUERY_OPTIONS["exhaust"]:
              if self.__limit:
                  raise InvalidOperation("Can't use limit and exhaust together.")
              if self.__collection.database.client.is_mongos:
                  raise InvalidOperation('Exhaust cursors are '
                                         'not supported by mongos')
              self.__exhaust = True
  
          self.__query_flags |= mask
          return self
docs: Set arbitrary query flags using a bitmask.
  
          To set the tailable flag:
          cursor.add_option(2)