No, the point of the function is to convert the type. It doesn't need to check anything, it just forcibly converts any argument to DC.

The compiler isn't complaining because the conversion isn't valid, it's complaining because it doesn't know that the string "dc" should be narrowed down to a literal type, and so it's kept it as broad as possible. Using `satisfies` lets it understand that it needs to do narrowing here.

In fairness I don't think this is the best case for `satisfies`, and some return type annotations would probably work a lot better here, and be clearer to read.