anchor.diff:  ''')
   class AppComponent {
     Iterable<Movie> movies = [];
  +  Iterable<String> users = [];
   
     fetchMovies(List<String> users) {
       var client = new TraktWebService();
  
positive.code:     <div class="mdl-grid">
        <div class="mdl-cell mdl-cell--3-col">
          <div class="mdl-textfield mdl-js-textfield">
            <input class="mdl-textfield__input" type="text" #username1 id="username1">
            <label class="mdl-textfield__label" for="username1">Trakt.tv username</label>
          </div>
        </div>
        <div class="mdl-cell mdl-cell--3-col">
          <div class="mdl-textfield mdl-js-textfield">
            <input class="mdl-textfield__input" type="text" #username2 id="username2">
            <label class="mdl-textfield__label" for="username2">Another username</label>
          </div>
        </div>
        <div class="mdl-cell mdl-cell--3-col">
          <div class="mdl-textfield mdl-js-textfield">
            <input class="mdl-textfield__input" type="text" #username3 id="username3">
            <label class="mdl-textfield__label" for="username3">Another (optional) username</label>
          </div>
        </div>
        <div class="mdl-cell mdl-cell--3-col">
          <div class="mdl-textfield mdl-js-textfield">
            <input class="mdl-textfield__input" type="text" #username4 id="username4">
            <label class="mdl-textfield__label" for="username4">Yet another (optional) username</label>
          </div>
        </div>
      </div>
  
      <div class="mdl-grid">
        <div class="mdl-cell mdl-call--12-col">
          <button
                class="mdl-button mdl-js-button mdl-button--raised mdl-js-ripple-effect"
                (click)="fetchMovies([username1.value, username2.value, username3.value, username4.value])">
              Find movies
          </button>
        </div>
      </div>
  
      <div class="mdl-grid">
        <div class="mdl-cell mdl-call--12-col">
          <ol>
            <li *ngFor="#movie of movies">
              {{ movie }}
  
negative.code: 
      driver(client, users, process);
    }
  
    addUser(userName) {
      users = []..addAll(users)..add(userName.value);
      userName.value = "";
      if( users.length > 1 ) {
        fetchMovies(users);
      }
    }
  }
  