code: function createPiGlow(callback) {
      var myPiGlow = new PiGlowBackend();
      var myInterface = piGlowInterface(myPiGlow);
  
      myPiGlow
          .on('initialize', function() {
              callback(null, myInterface);
          })
          .on('error', function(error) {
              callback(error, null);
          });
  }
docs: convenience constructor function