1 assert的作用
assert condition当condition不成立的时候，那么程序会raise一个AssertionError出来
所以其实 assert condition相当于：
if not condition:
raise AssertionError()2 实例
assert True程序通过
assert False程序抛出异常：
Traceback (most recent call last):
File "E:\ProgramData\Anaconda3\lib\site-packages\IPython\core\interactiveshell.py", line 2963, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "<ipython-input-3-a871fdc9ebee>", line 1, in <module>
assert False
AssertionError
assert 1!=1也会抛出异常
