functools.wraps

functools.wraps使う場合

import functools


def d(f):
    @functools.wraps(f)
    def w():
        """Wrapper docstring"""
        print('decorator')
        return f()
    return w


@d
def example():
    """Example docstring"""
    print('example')


print(example.__doc__)  # Example docstring

functools.wraps使わない場合

import functools


def d(f):
    #@functools.wraps(f)
    def w():
        """Wrapper docstring"""
        print('decorator')
        return f()
    return w


@d
def example():
    """Example docstring"""
    print('example')


print(example.__doc__)  # Wrapper docstring