//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();
}