From: Павел

main.py

In [14]: class LazyInit(type):
    ...:     def __new__(mcs, name, bases, namespace):
    ...:         namespace["__init__"] = lambda self, *args, **kwargs: vars(self).update(kwargs)
    ...:         return super().__new__(mcs, name, bases, namespace)
    ...:

In [15]: class Foo(metaclass=LazyInit):
    ...:     def __init__(self, name):
    ...:         pass
    ...:

In [16]: obj = Foo(name="John")

In [17]: obj.name
Out[17]: 'John'