Python /如何修饰类的方法部分而不修改所述类？

As an example, say I would like to decorate split() method of str class. (the example is representative of what I try to do, except I would like to decorate agg method of pandas DataFrame class :) )

至少，我得到同样的错误。

I prefer not to use @ nor to create a child of str class to keep things simple (and maybe it is why it is not working...)

我首先有一个问题：不能修改装饰器的参数吗？

def bla_addition(word):
    def decorator(func):
        def wrapper(*args, **kwargs):
            # Modify `my_list`
            word += 'bla'                #-> parameter word modified
            return  word.func(*args, **kwargs)
        return wrapper
    return decorator

added = bla_addition('blu')
split = added(str.split)
new_word = split('l')

Error generated: UnboundLocalError: local variable 'word' referenced before assignment

我很好奇知道为什么？

好的，因此为了绕过这个缺点，我创建了一个新的局部变量，但遇到了以下麻烦。

def bla_addition(word):
    def decorator(func):
        def wrapper(*args, **kwargs):
            # Modify `my_list`
            word2 = word + 'bla'         #-> local word2 used
            return  word2.func(*args, **kwargs)
        return wrapper
    return decorator

added = bla_addition('blu')
split = added(str.split)
new_word = split('l')

Error encountered: AttributeError: 'str' object has no attribute 'func'

拜托，你知道我该怎么办吗？

感谢您的帮助和建议。

PS: I took the way of using decorator without @ here: https://www.python-course.eu/python3_decorators.php I find it very helpful to avoid having to create a new 1-line function for split.