anchor.diff:                  sp.setString(DatabaseKeys.USER, CodeWarsAPI
                       .getErrorWithReason("time out"));
                 });
  -              setState(() {
  -                _user = null;
  -                _pop();
  -              });
  +              setState(() => _user = null);
  +              _pop();
               });
           }
         },
  
positive.code:               barrierDismissible: false);
            get(CodeWarsAPI.getUser(_user.username))
              ..then((val) {
                setState(() => _performChangeUser(val.body));
                SharedPreferences.getInstance().then((sp) {
                  sp.setString(DatabaseKeys.USER, val.body);
                });
  
negative.code:   }
  
    _performChangeUser(String _json) {
      var user = _json2user(_json, onError: (msg) => _me.displayWhenEmpty = msg);
      setState(() => _user = user);
    }
  
    _performChangeFriends(List<String> _allJson) {
      var all = _allJson
          .map(_json2user)
          .where((o) => null != o);
      setState(() => all.forEach(_friendUsers.add));
    }
  
    bool _addFriend(String _json) {
      CodeWarsUser friend = _json2user(_json);
      if (null != friend) {
        _friendUsers.add(friend);
        SharedPreferences.getInstance().then((sp) =>
            sp.setStringSet(DatabaseKeys.FRIENDS, _friendUsers.map((obj) => obj.username).toSet()));
        return true;
      }
      return false;
  