```ruby
module CoreSpring
  class Standard < APIModel
    attr_accessor :id, :dot_notation, :subject, :category, :sub_category, :standard, :grades
  end
end

```

Add domain attribute to Standard model.
user
```ruby
module CoreSpring
  class Standard < APIModel
    attr_accessor :id, :dot_notation, :subject, :category, :sub_category, :standard, :grades, :domain
  end
end

```
assistant