Question: Is there any Maple command to return true or false ?

Hello everyone!

I use this procedure to open my inbox:

>restart;
ShellExecute := define_external('ShellExecuteA', hwnd::(integer[4]), lpOperation::string, lpFile::string, lpParameters::string, lpDirectory::string, nShowCmd::integer[4], 'RETURN'::integer[4], LIB = "C:\\WINDOWS\\SYSTEM32\\shell32.dll"):
OpenBrowser := proc(someURL::string := "http://")

ShellExecute(0, " ", someURL, " ", " ", 1); NULL;

end proc:

Case 1:  I entered the correct email address of my friend who sent me the mail

>OpenBrowser("https://mail.google.com/mail/u/0/?tab=rm&ogbl#inbox/xxxxxxGqRZXPKXGzrrSrfHscdNWspRJF");

As a result, the content of the message I received was opened with full information.

Case 2:  When I enter an arbitrary email address that is not my friend, the result is that no content is displayed.

>OpenBrowser("https://mail.google.com/mail/u/0/?tab=rm&ogbl#inbox/yyyyyyGqRZXPKXGzrrSrfHscdNWspRJf");

On the email there is only the message: The conversation you requested could not be loaded.

May I ask:  Is there any Maple command to return true in case 1 and to return false in case 2 ?

Thank you very much for your help !