    # File lib/rubygame/music.rb, line 340
      def fade_out( fade_time )
        if( fade_time < 0 )
          raise ArgumentError, "fade time cannot be negative (got %.2f)"%fade_time
        end

        if current?
          result = SDL::Mixer.FadeOutMusic( (fade_time * 1000).to_i )
          if( result < 0 )
            raise Rubygame::SDLError, "Error fading out music: #{SDL.GetError()}"
          end
        end

        return self
      end