def decorator_get_function_duration(enable):

""":param enable:  是否须要统计函数执行耗时:return: """print("this is decorator_get_function_duration")def inner(func):    print('this is inner in decorator_get_function_duration')    @wraps(func)    def wrapper(*args, **kwargs):        print('this is a wrapper in decorator_get_function_duration.inner')        if enable:            start = time.time()            print(f"函数执行前：{start}")            result = func(*args, **kwargs)            print('[%s]`s enable was %s it`s duration : %.3f s ' % (func.__name__, enable, time.time() - start))        else:            result = func(*args, **kwargs)        return result    return wrapperreturn inner

def decorator_1(func):

print('this is decorator_1')@wraps(func)def wrapper(*args, **kwargs):    print('this is a wrapper in decorator_1')    return func(*args, **kwargs)return wrapper

def decorator_2(func):

print('this is decorator_2')@wraps(func)def wrapper(*args, **kwargs):    print('this is a wrapper in decorator_2')    return func(*args, **kwargs)return wrapper

@decorator_1 # 此处相当:decorator_1(decorator_2(decorator_get_function_duration(enable=True)(fun)))
@decorator_2 # = PayPal下载decorator_2(decorator_get_function_duration(enable=True)(fun))
@decorator_get_function_duration(enable=True) # = decorator_get_function_duration(enable=True)(fun)
def fun():

time.sleep(2)print("fun 执行完了～")

fun()

======== enable=False ============

"""
this is decorator_get_function_duration
this is inner in decorator_get_function_duration
this is decorator_2
this is decorator_1
this is a wrapper in decorator_1
this is a wrapper in decorator_2
this is a wrapper in decorator_get_function_duration.inner
fun 执行完了～
"""

======== enable=True ============