public function __construct($argname, $reason, \Exception $previous = null)
 {
     parent::__construct($reason, "Argument {$argname} is invalid", $previous);
 }
 public function __construct($reason, $code = 0, \Exception $previous = null)
 {
     $message = str("Unserialization failed: {0}", $reason);
     parent::__construct($reason, $message, $code, $previous);
 }