public string CreateCart(string clientId, string password)
{
if (string.IsNullOrWhiteSpace(clientId))
{
throw new ArgumentException(INVALID_CLIENTID_ERROR);
}
if (string.IsNullOrEmpty(password))
{
throw new ArgumentException(INVALID_PASSWORD_ERROR);
}
if (!_authenticator.Login(clientId, password))
{
throw new ArgumentException(LOGIN_IS_INVALID_ERROR);
}
var cartId = GenerateUniqueIdentifier();
var session = new Session(new Cart(_catalog), _internalClock.GetDateTime(), clientId);
_carts.Add(cartId, session);
return(cartId);
}