mysql_user with cfengine

mysql_user.cf

bundle agent mysql_user() {
vars:
  any::
    "users_to_check" slist => { "francois", "benoit" };
    "user_is_not_here" string => execresult("/usr/local/bin/mysql_user_check $(users_to_check)","noshell"); 
    
classes:
    "mysql_check_OK" expression => strcmp("$(user_is_not_here)", "OK");
    "mysql_check_NOK" expression => strcmp("$(user_is_not_here)", "NOK");

reports:
  mysql_check_OK.!mysql_check_NOK::
    "users exists";
 mysql_check_NOK.!mysql_check_OK::
    "users unknown";
}