> hashlib.algorithms_guaranteed
{'blake2s', 'sha256', 'sha3_512', 'sha1', 'shake_128', 'sha3_256', 'sha3_384', 'blake2b', 'sha3_224', 'sha512', 'md5', 'shake_256', 'sha224', 'sha384'}

> hashlib.algorithms_available
{'sha3_256', 'blake2b', 'md5', 'sha512_224', 'sha384', 'md4', 'sha256', 'sha512', 'whirlpool', 'sha224', 'sha512_256', 'shake_128', 'sha3_384', 'ripemd160', 'blake2s', 'sha3_512', 'sha1', 'sm3', 'shake_256', 'sha3_224', 'md5-sha1'}

> import hashlib
> m = hashlib.sha256()
> m.update(b" the spammish repetition")  #重复调用相当于，把bytes字节串相加。
> m.name  #hash算法的名字
'sha256'
> m.digest() #返回传入update()的数据的摘要
b'U<\x9bP\xb1\xa8\x9a\x9aE\x0f;h\xdb\x04\x11\xc1\x08\xfaH\xa7\t\xbfF\x91\x01\x13\xa1\x87\xb6\xd9`\x96'
> m.digest_size  #摘要的大小
> m.block_size  #hash算法内的块的大小
> m.hexdigest()  #返回一个字符串对象，一般用在安全的email或其他非binary环境
'553c9b50b1a89a9a450f3b68db0411c108fa48a709bf46910113a187b6d96096'
>

# -*- coding: utf-8 -*-
db = {
  'michael': 'e10adc3949ba59abbe56e057f20f883e',
  'bob': '878ef96e86145580c38c87f0410ad153',
  'alice': '99b1c2188db85afee403b1536010c2c9'
}

import hashlib

def calc_md5(password):
  m = hashlib.md5()
  m.update(password.encode('utf-8'))
  return m.hexdigest()

def login(user, password):
  return db[user] == calc_md5(password)
    

# 测试:
assert login('michael', '123456')
assert login('bob', 'abc999')
assert login('alice', 'alice2008')
assert not login('michael', '1234567')
assert not login('bob', '123456')
assert not login('alice', 'Alice2008')
print('ok')