Class function conversion should also respect type annotation

[hyangda]

When using functions to define attributes, the implicit coercion always takes priority:

    def COERCION_TEST(cls):
        return 123

    def COERCION_TEST(cls) -> str:
        return 123

    def COERCION_TEST(cls):
        return '123'

    def COERCION_TEST(cls) -> str:
        return '123'

all result in

>>> import config
>>> type(config.Configuration.COERCION_TEST)
<class 'int'>

Could we instead have the function return type annotation set the type, similarly to variables?

Thanks 😄