Type-checking decorator and bogosort.

bogo.py

#!/usr/bin/env python3

import random
import types

def typecheck(f: types.FunctionType) -> types.FunctionType:
    s = lambda x: repr(repr(x))

    def wrapper(*args, **kwargs):
        keys = list(f.__annotations__.keys())
        get = f.__annotations__.get

        for i, arg in enumerate(args):
            type = get(keys[i])
            if not isinstance(arg, type):
                raise TypeError(f'{s(arg)} is not an instance of {s(type)}')

        for key, arg in kwargs.items():
            type = get(key)
            if not isinstance(arg, type):
                raise TypeError(f'{s(arg)} is not an instance of {s(type)}')

        result = f(*args, **kwargs)
        type = get('return')

        if not isinstance(result, type):
            raise TypeError(f'return type is not an instance of {s(type)}')

        return result

    return wrapper

@typecheck
def is_sorted(x: list) -> bool:
    for i in range(len(x) - 1):
        if x[i] > x[i + 1]:
            return False
    return True

@typecheck
def bogosort(x: list) -> list:
    while not is_sorted(x):
        random.shuffle(x)
    return x

x = [1, 2, 3, 4, 5]
random.shuffle(x)
print(bogosort(x))