code: def setAllowed(self, laneID, allowedClasses):
          
          if isinstance(allowedClasses, str):
              allowedClasses = [allowedClasses]
          self._connection._beginMessage(tc.CMD_SET_LANE_VARIABLE, tc.LANE_ALLOWED, laneID,
                                         1 + 4 + sum(map(len, allowedClasses)) + 4 * len(allowedClasses))
          self._connection._packStringList(allowedClasses)
          self._connection._sendExact()
docs: setAllowed(string, list) -> None
  
          Sets a list of allowed vehicle classes. Setting an empty list means all vehicles are allowed.