code: function(obj) {
              var rest = slice.call(arguments, 1);
  
              for (var i = 0; i < rest.length; i++) {
                  var source = rest[i];
  
                  if (source) {
                      for (var prop in source) {
                          obj[prop] = source[prop];
                      }
                  }
              }
  
              return obj;
          }
docs: Extends the first object with the properties of the following objects.
  @method extend
  @param {object} obj The target object to extend.
  @param {object} extension* Uses to extend the target object.