Mix-in class for use with a TravelConnector whose destination may vary. To use a VarDest list it before the TravelConnector class in the class list of your object/class definition and use its caldDest method to define the expression or method yielding the connector's destination. This is only necessary if the value of this method might change in the course of one turn (when it will be evaluated multiple times), as may, for example, occur if it contains an element of randomness.

class VarDest :   object