public Task AddShortlistAsync(ShortlistQueryModel shortlist)
 {
     ShortlistDB.Instance.Add(shortlist);
     return Task.FromResult(0);
 }
 public Task UpdateShortlistAsync(ShortlistQueryModel shortlist)
 {
     var list = ShortlistDB.Instance.First(s => s.Date == s.Date);
     if (list != shortlist) { list.Selection = shortlist.Selection; }
     return Task.FromResult(0);
 }