static void Main(string[] args) { var repository = new SqlRepository(); var service = new PasswordCheckerService(repository); service.AddValidationRule(x => { if (x == null) { throw new ArgumentException($"{x} is null arg"); } return(Tuple.Create(true, "Password is Ok. User was created")); } ); service.AddValidationRule(x => { if (x.Length <= 7) { return(Tuple.Create(false, $"{x} length too short")); } return(Tuple.Create(true, "Password is Ok. User was created")); }) }