public function check_environment(array $errors = array())
 {
     $errors = array();
     if (!is_object($this->object) || !$this->object instanceof Core_IWorker) {
         $errors[] = 'Invalid worker object. Workers must implement Core_IWorker';
     }
     $object_errors = $this->object->check_environment();
     if (is_array($object_errors)) {
         $errors = array_merge($errors, $object_errors);
     }
     return parent::check_environment($errors);
 }