The right-associative version of reduce, also known as `foldr`.

def reduceRight(self, func):
        """ The right-associative version of reduce, also known as `foldr`.
        """
        #foldr = lambda f, i: lambda s: reduce(f, s, i)
        x = self.obj[:]
        x.reverse()
        return self._wrap(functools.reduce(func, x))