[Python] How do I instantiate a subclass from a superclass instance in Python? [closed]

I want to achieve this effect, ideally without much boilerplate:

class Vehicle:
def __init__(self, license_plate) -> None:
self.license_plate = license_plate
# Several other fields...

register(self) # Expensive!

class Truck(Vehicle):
def __init__(self, v: Vehicle, commercial_license) -> None:
# Move all of v's fields into self without calling Vehicle.__init__ ...

self.commercial_license = commercial_license

register_commercial(self)


(For example, in C++, I could call the superclass's default move constructor in the subclass constructor's initializer list.)

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