private async Task VerifyCodeAsync()
        {
            var success = await SignInService.AuthAsync(PhoneNumber.Value, Code.Value);

            if (!success)
            {
                // we should say verification code is failed
                return;
            }

            await UserInfoService.UpdateUserInfo();

            if (UserInfoService.IsNewUser())
            {
                await NavigationService.Navigate <UserTypeSelectorViewModel>();
            }
            else
            {
                await NavigationService.Navigate <HomeViewModel>();
            }
        }