code: function (location, keyPath) {
          var vm = this._vm;
          var ref = this._root.child(location);
  
          keyPath = isString(keyPath)
              ? keyPath
              : ref.ref().key();
  
          var firebaseValue = new FirebaseValue(vm, keyPath, ref);
  
          set(this._references, keyPath, firebaseValue);
  
          return firebaseValue;
      }
docs: Binds a Firebase value/object to a view model keypath
  
  @param keyPath {String} The Firebase reference will be bound to this keyPath in the view model
  @param location {String} The relative to the root path of the Firebase reference