withFieldGroup not return from createFormHook

in documentation it's showning there is an function called withFieldGroup. But I am not getting it. Documentation: https://tanstack.com/form/latest/docs/framework/react/guides/form-composition#reusing-groups-of-fields-in-multiple-forms

Form Composition | TanStack Form React Docs

A common criticism of TanStack Form is its verbosity out-of-the-box. While this can be useful for educational purposes helping enforce understanding our APIs it's not ideal in production use cases. As...