Making carmen 1.x work with Formtastic (file under app/lib in my app)

country_select.rb

class CountryInput < Formtastic::Inputs::CountryInput
  def to_html
    raise "To use the :country input, please install a country_select plugin, like this one: https://github.com/jamesds/country-select" unless builder.respond_to?(:country_select)
    input_wrapping do
      label_html <<
      builder.country_select(method, priority_countries, input_options)
    end
  end
  
  def priority_countries
    options[:priority_countries] || {priority: ['US','CA']}
  end
    
end

Have you gotten the subregions to work with active admin and carmen?