private function getOAuth2AuthorizationHeader($OAuth2AccessToken){
      if(!$OAuth2AccessToken instanceof OAuth2AccessToken){
         throw new SdkException("Internal Error. The OAuth 2 configuration is not complete.");
      }

      $accessToken = $OAuth2AccessToken->getAccessToken();
      $AuthorizationHeader = "Bearer " . $accessToken;
      return $AuthorizationHeader;
    }