Access to ObjectValidator._properties

I want to create a type by modifying another type like below.
But, I don't want to export `typeAProps`.

I want to create `TypeB` from `TypaA._properties` but `_properties` is private.
Could you add access to `_properties` to `ObjectValidator`?
```
export const typeAProps = {
id: v.string().required(),
name: v.string().required(),
...
};
export const TypeA = annotate(
{ title: "TypeA" },
v.object(typeAProps)
);

// another file
export const TypeB = annotate(
{ title: "TypeB" },
v.object({
...typeAProps, // => ...TypaA._properties
id: v.number().required(),
})
);
```