# app/avo/resources/course.rb
class Avo::Resources::Course < Avo::BaseResource
  def filters
    filter Avo::Filters::CourseCountryFilter
    filter Avo::Filters::CourseCityFilter
  end
end
```

The country filter is pretty straightforward. Set the query so the `country` field to be one of the selected countries and the `options` are the available countries as `Hash`.

```ruby{6,10}