def all
      response = @config.http.get("#{@config.base_merchant_path}/add_ons")
      attributes_collection = response[:add_ons]
      attributes_collection.map do |attributes|
        AddOn._new(attributes)
      end
    end
def all
      response = @config.http.get("#{@config.base_merchant_path}/add_ons")
      attributes_collection = response[:add_ons]
      attributes_collection.map do |attributes|
        AddOn._new(attributes)
      end
    end
:nodoc