uuid

function uuid(){
  return sprint_f("%04x%04x-%04x-%04x-%04x-%04x%04x%04x", mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff), 
  mt_rand(0, 0x0fff) | 0x4000,
  mt_rand(0, 0x3fff) | 0x8000,
  mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
  );
}