猫史档案馆

注明：编者用的是python3.10.9

 

先看一串代码：

def a():
    a()
a()

这是喵的递归，一般只能递归1022次，运行后就会报错：

Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>
    a()
  File "<pyshell#2>", line 2, in a
    a()
  File "<pyshell#2>", line 2, in a
    a()
  File "<pyshell#2>", line 2, in a
    a()
  [Previous line repeated 1022 more times]
RecursionError: maximum recursion depth exceeded

其中，[Previous line repeated 1022 more times]告诉我们报错信息过长，已经压缩。

但是，我们能不能展开呢？

答案是：能。

想展开，得先研究python是如何折叠报错信息的：

错误
错误
错误
错误
错误
错误
错误
……

因为都是一样的“错误”，并且连续所以就能折叠。

但如果我们把它弄成不连续的就不可以了。

def a():
    b()

def b():
    a()

a()

运行（这里用的是cmd）：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
  File "<stdin>", line 2, in b
  File "<stdin>", line 2, in a
RecursionError: maximum recursion depth exceeded

我们成功地展开了报错信息！

最后，作者只想说：现在电脑卡到打一个“编程猫”都要等10秒……所以递归虽有趣，但也要谨慎使用！