Specs: registerElement(registerElement(...)) failed to work as expected

sky/examples/calculator/buttons.sky

Index: sky/examples/calculator/buttons.sky
diff --git a/sky/examples/calculator/buttons.sky b/sky/examples/calculator/buttons.sky
index 1b758d811ca83845497eb35d133d09f1bc837108..29c59c35e44904adc918f7b387e0df04e6f891ae 100644
--- a/sky/examples/calculator/buttons.sky
+++ b/sky/examples/calculator/buttons.sky
@@ -55,25 +55,25 @@ SKY MODULE - button widgets for calculator
 
 <script>
  module.exports = {
-   ThreeDButtonElement: module.registerElement({
-     tagName: 'graybutton',
-     shadow: true,
-     constructor: class extends AbstractButton {
+   ThreeDButtonElement: module.registerElement(
+     class extends AbstractButton {
+       static get tagName() { return 'graybutton'; }
+       static get shadow() { return true; }
        constructor (module) {
          super(module);
          this.shadowRoot.append(module.document.findId('threed-button-shadow-tree').cloneNode(true));
        }
-     },
-   }),
-   FlatButtonElement: module.registerElement({
-     tagName: 'graybutton',
-     shadow: true,
-     constructor: class extends AbstractButton {
+     }
+   ),
+   FlatButtonElement: module.registerElement(
+     class extends AbstractButton {
+       static get tagName() { return 'flatbutton'; }
+       static get shadow() { return true; }
        constructor (module) {
          super(module);
          this.shadowRoot.append(module.document.findId('flat-shadow-tree').cloneNode(true));
        }
-     },
-   }),
+     }
+   ),
  };
 </script>