code: def clone(self, choices):
          
          return self.__class__(
              self.name,
              choices,
              self.label,
              self.description,
              self.multiple,
              self.viewFactory)
docs: Make a copy of this parameter, supply different choices.
  
          @param choices: A sequence of L{Option} instances.
          @type choices: C{list}
  
          @rtype: L{ChoiceParameter}