def method_missing(name, *args, **config, &block)
      if respond_to_missing?(name)
        config[:type] = name
        on(*args, config, &block)
      else
        super
      end
    end
def method_missing(name, *args, **config, &block)
      if respond_to_missing?(name)
        config[:type] = name
        on(*args, config, &block)
      else
        super
      end
    end
Handle custom option types. Will fall back to raising an
 exception if an option is not defined.