code: def subscribe(self, objectID, varIDs=None, begin=0, end=2**31 - 1):
          
          if varIDs is None:
              if tc.LAST_STEP_VEHICLE_NUMBER in self._retValFunc:
                  varIDs = (tc.LAST_STEP_VEHICLE_NUMBER,)
              else:
                  varIDs = (tc.ID_LIST,)
          self._connection._subscribe(
              self._subscribeID, begin, end, objectID, varIDs)
docs: subscribe(string, list(integer), double, double) -> None
  
          Subscribe to one or more object values for the given interval.