attrfunc.py

import functools
import types

def attrfunc(func=None, **attrs):
    if not func:
        return functools.partial(attrfunc, **attrs)
    return AttrFunc(func, **attrs)

class AttrFunc:
    def __init__(self, func, **attrs):
        self.func = func 
        for k, v in attrs.items():
            setattr(self, k, v)

    def __call__(self, *args, **kwargs):
        return self.func(*args, **kwargs)

    def __get__(self, obj, cls):
        if obj is None:
            return self
        return types.MethodType(self, obj)

class Foo:
    @attrfunc(foo=5, bar=5)
    def hello(self, x, y):
        print(x + y)

f = Foo()
print(f"Attribute {f.hello.foo=}")
print(f"Attribute {f.hello.bar=}")
f.hello(5, 5)