[Python] How to tell Python to re-evaluate a parent class method's interface? [duplicate]

Over the years, I can't count how many times I wanted to do something like this in Python:

class A:
DEFAULT_MESSAGE = "Unspecified Country"

def do_it(message=DEFAULT_MESSAGE):
print(message)

class B(A):
DEFAULT_MESSAGE = "Mexico"


And have this result in:

> A().do_it()
Unspecified Country
> B().do_it()
Mexico


Without having to redefine the method:

class B(A):
DEFAULT_MESSAGE = "Mexico"

def do_it(message=DEFAULT_MESSAGE):
super().do_it(message)


Or do an arguably bad design pattern of setting the default message to None for the method, and instead reading the DEFAULT_MESSAGE in the implementation of the method.

Is there a better, more DRY design-pattern that helps with this? Or is there some way to tell Python to re-evaluate the interfaces on parent class methods when defining a new, sub-class?

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