public void AddCourier(BlizhMail b)
 {
     try
     {
         using (var db = new LiteDatabase(@"Courier.db"))
         {
             LiteCollection <BlizhMail> collection = db.GetCollection <BlizhMail>("Blitz");
             collection.Insert(b);
         }
     }
     catch (Exception)
     {
         throw;
     }
 }
        /// <summary>
        /// Метод возвращет Blitz по его ID
        /// </summary>
        /// <param name="e">ID курьерской накладной</param>
        /// <returns>Найденная курьерская наладная</returns>
        public BlizhMail GetBlitzId(int e)
        {
            BlizhMail blitzKN = null;

            try
            {
                using (var db = new LiteDatabase(@"Courier.db"))
                {
                    LiteCollection <BlizhMail> collection = db.GetCollection <BlizhMail>("Blitz");
                    blitzKN = (BlizhMail)collection.Find(d => d.DeliveryNoteId == e);
                }
            }
            catch (Exception)
            {
            }

            return(blitzKN);
        }