private void ValidBirthYearButton_Click(object sender, EventArgs e) { List <string> yearList = new() { "1900", "1956", "2000", DateAndTime.Now.Year.ToString() }; foreach (var currentYear in yearList) { Debug.WriteLine(Validates.ValidateBirthYear(currentYear) ? $"{currentYear} is valid" : $"{currentYear} is not valid"); } }