public bool TryArilineLogin(string userName, string password, out LoginToken <AirlineCompany> token)
 {
     throw new NotImplementedException();
 }
 public bool TryCustomerLogin(string userName, string password, out LoginToken <Customer> token)
 {
     throw new NotImplementedException();
 }
 public bool TryAdminLogin(string userName, string password, out LoginToken <Administrator> token)
 {
     throw new NotImplementedException();
 }