code: function(kind) {
              ko.bindingHandlers[kind] = {
                  init: function() {
                      return { controlsDescendantBindings: true };
                  },
                  update: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
                      var settings = widget.getSettings(valueAccessor);
                      settings.kind = kind;
                      extractParts(element, settings);
                      widget.create(element, settings, bindingContext, true);
                  }
              };
  
              ko.virtualElements.allowedBindings[kind] = true;
              composition.composeBindings.push(kind + ':');
          }
docs: Creates a ko binding handler for the specified kind.
  @method registerKind
  @param {string} kind The kind to create a custom binding handler for.