PKHeX.SAV_EventFlagsXY.getFlagNum C# (CSharp) Method

        private int getFlagNum(CheckBox chk)
        {
            try
            {
                string source = chk.Name;
                return Convert.ToInt32(source.Substring(Math.Max(0, source.Length - 4)));
            }
            catch { return 0; }
        }
        private void changeCustomBool(object sender, EventArgs e)