public void RemoveFromLines(OrderLine value)
 {
     if (_Lines.Contains(value))
        {
        _Lines.Remove(value);
        }
 }
 public void AddToLines(OrderLine value)
 {
     if (!(_Lines.Contains(value)))
        {
        _Lines.Add(value);
        }
 }
 public IList<OrderLine> ChoicesRemoveFromLines(OrderLine value)
 {
     return _Lines.ToList();
 }