public function requireAuthentication(HTTPRequest $request)
    {
        $authenticator = $this->getAuthenticator($request);
        if (!$authenticator) {
            return false;
        }

        $member = $authenticator->authenticate($request);
        if ($member instanceof Member) {
            return $member;
        }
        // Note: The authenticator class itself may also throw an exception when called
        throw new ValidationException('Authentication failed.', 401);
    }