//Post method data saving
        public async Task <BillingAddress> AddBillingAddress(BillingAddress billingAddress)
        {
            var result = await appDBContext.BillingAddress.AddAsync(billingAddress);

            await appDBContext.SaveChangesAsync();

            return(result.Entity);
        }
 public Task <BillingAddress> UpdateBillingAddress(BillingAddress billingAddress)
 {
     throw new NotImplementedException();
 }