hash_sort.rb

  def self.alphabetized_by_label
    initial_hash = all.group_by(&:product_type_name)
    initial_hash.each do |key, value|
      initial_hash[key] = value.sort{|x,y| x.en_name <=> y.en_name}
    end
    {}.tap do |final_hash|
      initial_hash.keys.sort.each do |key|
        final_hash[key] = initial_hash[key]
      end
    end
  end