[Python] Class factory builder with correct signature

I'm trying to implement a factory design pattern (python 3.12+) and I'm having some trouble keeping my factory signature correct. Maybe what I'm trying to do is not conventional and I should look for an other design pattern.

Let's take this code example :

from typing import ParamSpec, TypeVar

P = ParamSpec("P")
T = TypeVar("T")

class Base:
@classmethod
def factory(cls, *args.args, **kwargs.kwargs):
def f(parent):
return cls(parent, *args, **kwargs)
return f

class CustomA(Base):
def __init__(self, parent:str, arg1:int, arg2:int):
print(f"Instantiate CustomA with arg {parent}, {arg1}, {arg2}")

#Ideally I would like this method signature to match the CustomA constructor signature
#without the parent argument
test = CustomA.factory(1, 2)
print(test) #Does correctly return a method
a = test("parent")
print(a) # That when is called return the object correctly instantiate


In my use case I would like to partially prepare a method call to instantiate an object while missing a parameter for that. Later I would complete that partial call to actually instantiate the object. In order to do so I implemented a factory builder method in the parent class that would allow me to easily implement that feature in all my child class. The code above is working fine, but I lose the signature and therefore IDE IntelliSense for the subclass constructor.

As you can see I tried to use ParamSpec and TypeVar but I don't really understand how they work. Maybe a different approach using the new method, or a decorator would be more suitable ? I didn't had success so far with those other approach.

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