import inspect

def make_everything_classmethod(cls):
    for name, method in inspect.getmembers(cls, predicate=inspect.isfunction):
        print(f"Making {name} into a classmethod.")
        setattr(cls, name, classmethod(method))
    return cls

@make_everything_classmethod
class Serializer:
    def foo(cls):
        return 1
    def bar(cls):
        return 2
    def baz(cls):
        return 3

print(Serializer.foo())
print(Serializer.bar())
print(Serializer.baz())