code: def subscribeContext(self, objectID, domain, dist, 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._subscribeContext(
              self._contextID, begin, end, objectID, domain, dist, varIDs)
docs: subscribeContext(string, int, double, list(integer), double, double) -> None
  
          Subscribe to objects of the given domain (specified as domain=traci.constants.CMD_GET_<DOMAIN>_VARIABLE),
          which are closer than dist to the object specified by objectID.