def METHOD_NAME(self, v=None):
    if v is None:
        # Attn! We're walking nodes in reverse
        for i in range(len(self.graph)-1, -1, -1):
            if self.rindex[i] == 0:
                self.METHOD_NAME(i)
    else:
        self.begin_visiting(v)
        while not self.vS.is_empty_front():
            self.visit_loop()