```ruby
# frozen_string_literal: true
require 'facebook_ads/model'

module FacebookAds
  class AdSet < FacebookAds::Model
    field :targeting
    field :created_at
  end
end
```

Use actual field name from Facebook
user
```ruby
# frozen_string_literal: true
require 'facebook_ads/model'

module FacebookAds
  class AdSet < FacebookAds::Model
    field :targeting
    field :created_time
  end
end
```
assistant