/**
  * @param array                          $request_parameters
  * @param \OAuth2\Client\ClientInterface $client
  *
  * @throws \OAuth2\Exception\BadRequestExceptionInterface
  *
  * @return array
  */
 private function getTokenTypeInformation(array $request_parameters, ClientInterface $client)
 {
     $token_type = $this->getTokenTypeFromRequest($request_parameters);
     if (!$client->isTokenTypeAllowed($token_type->getTokenTypeName())) {
         throw $this->getExceptionManager()->getBadRequestException(ExceptionManagerInterface::ERROR_INVALID_REQUEST, sprintf('The token type "%s" is not allowed for the client.', $token_type->getTokenTypeName()));
     }
     return $token_type->getTokenTypeInformation();
 }