装饰器.py

from functools import wraps

def logged(func):
    @wraps(func) # 复制原始函数的名称、文档等内容到新函数。
    def with_logging(*args, **kwargs):
        print (func.__name__ + " was called")
        return func(*args, **kwargs)
    return with_logging

@logged
def f(x):
   """does some math"""
   return x + x * x

f(1)
print (f.__name__ ) # prints 'f'
print (f.__doc__)  # prints 'does some math'