True, if lnode and rnode are located on different forks of IF/TRY

def differentForks(self, lnode, rnode):
        """True, if lnode and rnode are located on different forks of IF/TRY"""
        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