c# Create custom exception

  public class CertNotValidException : Exception
    {
        public CertNotValidException()
            : base() { }
 
        public CertNotValidException(string message)
            : base(message) { }
 
        public CertNotValidException(string format, params object[] args)
            : base(string.Format(format, args)) { }
 
        public CertNotValidException(string message, Exception innerException)
            : base(message, innerException) { }
 
        public CertNotValidException(string format, Exception innerException, params object[] args)
            : base(string.Format(format, args), innerException) { }
    }