code: function setBrightnessOfLed(callback) {
      var ledIndex = 8;
      
      var setBrightnessOfLedInterval = setInterval(function() {
          if (ledIndex >= 0) {
              dot3k.barGraph.setBrightnessOfLed(ledIndex, 0);
              
              ledIndex--;
          } else {
              clearInterval(setBrightnessOfLedInterval);
              
              if (callback) {
                  callback();
              }
          }
      }, 500);
  }
docs: Sets the brightness of each individual LED.
  @param {Function} callback A function to call when the operation has finished.