_define_after_model_callback

# File activemodel/lib/active_model/callbacks.rb, line 136
      def _define_after_model_callback(klass, callback)
        klass.define_singleton_method("after_#{callback}") do |*args, &block|
          options = args.extract_options!
          options[:prepend] = true
          conditional = ActiveSupport::Callbacks::Conditionals::Value.new { |v|
            v != false
          }
          options[:if] = Array(options[:if]) << conditional
          set_callback(:"#{callback}", :after, *(args << options), &block)
        end
      end