# File lib/active_model/validations.rb, line 121
      def validate(*args, &block)
        options = args.extract_options!
        if options.key?(:on)
          options = options.dup
          options[:if] = Array.wrap(options[:if])
          options[:if] << "validation_context == :#{options[:on]}"
        end
        args << options
        set_callback(:validate, *args, &block)
      end