public void AddorUpdate(CanItem can)
        {
            var found = _stock.GetAll().FirstOrDefault(item => item.Flavour.ToLower() == can.Flavour.ToLower());

            if (found == null)
            {
                _stock.Add(can);
            }
            else
            {
                _stock.Update(can);
            }
        }
 public void Remove(CanItem can)
 {
     Cans.RemoveAll(item => item.Flavour == can.Flavour);
 }
 public void Update(CanItem can)
 {
     Remove(can);
     Add(can);
 }
 public void Add(CanItem can)
 {
     Cans.Add(can);
 }