python 函数耗时

import string
import random
import time
import functools

def list_from_2d_np(np_array):
    """
    convert a 2d numpy array to a list
    """
    shape = np_array.shape
    total = shape[0] * shape[1]
    new_array = np_array.reshape(total)
    return list(new_array)


def generate_random_str(length=20):
    return ''.join(random.choice(string.digits + string.ascii_letters) for _ in range(length))


def generate_time_stamp():
    time_unique_id = time.strftime("%Y-%m-%d-%H-%M-%S", time.localtime())
    return time_unique_id


def time_it(fn):
    @functools.wraps(fn)
    def inner(*args, **kwargs):
        start = time.time()
        fn(*args, **kwargs)
        end = time.time()
        print("Time cost for function `{}`: {}".format(fn.__name__, (end - start)))
    
    return inner