Python assert 用法

Python中assert用来判断语句的真假，如果为假的话将触发AssertionError错误

python help document的解释：

Assert statements are a convenient way to insert debugging assertions into a program:

例：

>>> a = 3
>>> assert a ==3
>>> a = 2
>>> assert a ==3
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError

例2：