'/^[a-zA-Z][a-zA-Z0-9\-_]{1,19}$/', 'namespace' => '/^[a-zA-Z\-_][a-zA-Z0-9\-_.]*$/', 'domain' => '/^(?!-)(?:[a-zA-Zd-]{0,62}[a-zA-Zd].){1,126}(?!d+)[a-zA-Zd]{1,63}$/', 'time_slot' => '/^\d{1,2}:\d{1,2}(:\d1,2})?-\d{1,2}:\d{1,2}(:\d1,2})?$/', ];