anchor.diff:    So we replace `selectedHero` with `hero` everywhere in our new template. That's our only change.
     The result looks like this:
   
  -+makeExample('toh-3/ts/app/hero-detail.component.ts', 'template', 'hero-detail.component.ts (template)')(format=".")
  ++makeExample('toh-3/ts/app/hero-detail.component.ts', 'template', 'app/hero-detail.component.ts (template)')(format=".")
   
   :marked
     Now our hero detail layout exists only in the `HeroDetailComponent`.
  
positive.code:   
    We solve the problem by relocating the `Hero` class from `app.component.ts` to its own `hero.ts` file.
  
  +makeExample('toh-3/ts/app/hero.ts', null, 'hero.ts (Exported Hero class)')(format=".")
  
  :marked
    We export the `Hero` class from `hero.ts` because we'll need to reference it in both component files. 
    Add the following import statement near the top of both `app.component.ts` and `hero-detail.component.ts`.
  
  +makeExample('toh-3/ts/app/hero-detail.component.ts', 'hero-import', 'hero-detail.component.ts and app.component.ts (Import the Hero class)')
  
  :marked
    #### The *hero* property is an ***input***
  
negative.code:   ### Separating the Hero Detail Component
    Add a new file named `hero-detail.component.ts` to the `app` folder and create `HeroDetailComponent` as follows.
  
  +makeExample('toh-3/ts/app/hero-detail.component.ts', 'v1', 'app/hero-detail.component.ts (initial version)')(format=".")
  .l-sub-section
    :marked
      ### Naming conventions
  