protected function loadApplication(LoginAttempt $loginAttempt)
    {
        // retrieve Application
        if (!$application = $this->applicationLoader->retrieveByApiKeyAndSecret(
            $loginAttempt->getData('client_api_key'),
            $loginAttempt->getData('client_secret')
        )) {
            throw new InvalidGrantException(
                $loginAttempt,
                'Any application found for given api_key / secret.'
            );
        }

        return $application;
    }