anchor.diff:      ..append(ti);
     button
       ..onClick.listen((e) {
  -          st.deleteItemInStorage(task);
  -          li.parent.remove();
  -        })
  +      st.deleteItemInStorage(task);
  +      li.parent.remove();
  +    })
       ..text = "Delete";
     li
       ..classes.add('singletask')
  
positive.code:   ButtonElement button = new ButtonElement();
    ti
      ..value = task.summary
      ..classes.add('summarytext');
    fe
      ..onSubmit.listen((e) {
        e.preventDefault();
        task.summary = ti.value;   
        st.editItemInStorage(task);
        li.parent.children[0].classes.toggle('hidesingletask');
        li.classes.toggle('hideedittask');
  
negative.code:   li
      ..classes.add('singletask')
      ..onClick.listen((e) {
        li.classes.toggle('hidesingletask');
        li.parent.children[1].classes.toggle('hideedittask');
      })
      ..append(p);
    return li;
  }
  