assert

Python assert(断言)可以分辨后面的判断是否正确，如果错误会报错

a = 1
assert type(a) is int
print('No problem')

输出结果：

No problem

a = '1'
assert type(a) is int
print('No problem')

输出结果：

Traceback (most recent call last):
   File "D:/test.py", line 3, in <module>
     assert type(a) is int
AssertionError