public function __construct($data)
 {
     parent::__construct();
     foreach ($data as $key => $value) {
         if (is_object($value) || is_array($value)) {
             $this->_data[$key] = new SafeData_Object($value);
         } else {
             $this->_data[$key] = new SafeData_Value($value);
         }
     }
 }
 public function __construct($value)
 {
     parent::__construct();
     $this->_data = $value;
 }