code: def differentForks(self, lnode, rnode):
          
          ancestor = self.getCommonAncestor(lnode, rnode, self.root)
          parts = getAlternatives(ancestor)
          if parts:
              for items in parts:
                  if self.descendantOf(lnode, items, ancestor) ^ \
                     self.descendantOf(rnode, items, ancestor):
                      return True
          return False
docs: True, if lnode and rnode are located on different forks of IF/TRY