36     public function validate($string, $config, $context) {
 
   37         $string = trim($string);
 
   38         if (!$this->case_sensitive) {
 
   40             $string = ctype_lower($string) ? $string : strtolower($string);
 
   42         $result = isset($this->valid_values[$string]);
 
   44         return $result ? $string : 
false;
 
   52     public function make($string) {
 
   53         if (strlen($string) > 2 && $string[0] == 
's' && $string[1] == 
':') {
 
   54             $string = substr($string, 2);
 
   59         $values = explode(
',', $string);