TS error when setting docs_url/redoc_url/openapi_url to null

[paullocsin]

The documentation for docs_url (and redoc_url and openapi_url) say the value can be null but getting ts error

Type 'null' is not assignable to type 'string | undefined'

because the actual types are

    docs_url?: string;
    redoc_url?: string;
    openapi_url?: string;