private async void MergePatients()
{
PatientsMergeOn = false;
await DatabaseHandler.Instance.MergePatients(PatientsToMerge.Select(item => item.Id).ToList());
PatientsToMerge = new ObservableCollection <LocalPatient>();
MergeButtonVisibility = Visibility.Visible;
MergePatientsVisibility = Visibility.Collapsed;
}