accepts_nested_attributes_for

# File activerecord/lib/active_record/nested_attributes.rb, line 189
      def accepts_nested_attributes_for(*attr_names)
        options = { :allow_destroy => false }
        options.update(attr_names.extract_options!)
        options.assert_valid_keys(:allow_destroy, :reject_if)

        attr_names.each do |association_name|
          if reflection = reflect_on_association(association_name)
            type = case reflection.macro
            when :has_one, :belongs_to
              :one_to_one
            when :has_many, :has_and_belongs_to_many
              :collection
            end

            reflection.options[:autosave] = true
            self.reject_new_nested_attributes_procs[association_name.to_sym] = options[:reject_if]

            # def pirate_attributes=(attributes)
            #   assign_nested_attributes_for_one_to_one_association(:pirate, attributes, false)
            # end
            class_eval %{
              def #{association_name}_attributes=(attributes)
                assign_nested_attributes_for_#{type}_association(:#{association_name}, attributes, #{options[:allow_destroy]})
              end
            }, __FILE__, __LINE__
          else
            raise ArgumentError, "No association found for name `#{association_name}'. Has it been defined yet?"
          end
        end
      end