public function delUserBlocked($user_id, $user_blocked_id)
    {
        if (!is_numeric($user_id) || 0 >= $user_id) {
            throw new InvalidArgumentException(
                "DeleteUserBlocked user_id field should be positive integer", 404);
        }

        if (!is_numeric($user_blocked_id) || 0 >= $user_blocked_id) {
            throw new InvalidArgumentException(
                "DeleteUserBlocked user_blocked_id field should be positive integer", 404);
        }

        $command = $this->client->getCommand(
            'DeleteUserBlocked',
            array('user_id' => $user_id, 'blocked_user_id' => $user_blocked_id)
        );

        return $this->executeCommand($command);
    }