custom static method
- Expression<int> ? id,
- Expression<String> ? userId,
Implementation
static Insertable<AccountRow> custom({
  Expression<int>? id,
  Expression<String>? userId,
}) {
  return RawValuesInsertable({
    if (id != null) 'id': id,
    if (userId != null) 'user_id': userId,
  });
}