postman pre-request script (random array)

var arr_timezone = ["Africa/Tunis" , "Asia/Gaza" , "America/Costa_Rica", "America/Puerto_Rico" , "Atlantic/Cape_Verde" , "Europe/London" , "Europe/Dublin" , "Europe/Oslo" , "Europe/Rome"];

var rand_arr_timezone = Math.floor(Math.random() * arr_timezone.length);

var alert_rand_arr_timezone = arr_timezone[rand_arr_timezone];
pm.environment.set("alert_rand_arr_timezone", alert_rand_arr_timezone);