SIPSorcery.SIP.SIPEventDialogStateEvent.IsValid C# (CSharp) Method

        public static bool IsValid(string value)
        {
            if (value.IsNullOrBlank())
            {
                return false;
            }
            else if (value.ToLower() == "cancelled" || value.ToLower() == "error" || value.ToLower() == "local-bye" ||
                value.ToLower() == "rejected" || value.ToLower() == "replaced" || value.ToLower() == "remote-bye" ||
                value.ToLower() == "timeout")
            {
                return true;
            }
            else
            {
                return false;
            }
        }