src/js/my-element.js
/**
   * Implement `render` to define a template for your element.
   *
   * You must provide an implementation of `render` for any element
   * that uses LitElement as a base class.
   */
Implement `render` to define a template for your element.

You must provide an implementation of `render` for any element
that uses LitElement as a base class.
Implement ` render ` to define a template for your element . You must provide an implementation of ` render ` for any element that uses LitElement as a base class .
render(){
    return html`
      Web Components are 
      <span class="mood">${this.mood}</span>!
      <slot>A paragraph</slot>
    `;
  }
render ( ) { return html ` ${ this . mood } ` ; }
Implement `render` to define a template for your element.
Implement ` render ` to define a template for your element .
/**
     * `render` must return a lit-html `TemplateResult`.
     *
     * To create a `TemplateResult`, tag a JavaScript template literal
     * with the `html` helper function:
     */