import functools


def dec(func=None):
    if func is None:
        return lambda f: dec(f)
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        print('wrapper')
        return func(*args, **kwargs)

    return wrapper


def foo1():
    print('bar1')

@dec
def foo2():
    print('bar2')


@dec()
def foo3():
    print('bar3')


foo1()
foo2()
foo3()
print(foo1.__name__)
print(foo2.__name__)
print(foo3.__name__)