code: public OAuthCredentials checkToken(String oauthToken) throws JinxException {
      JinxUtils.validateParams(oauthToken);
  
      Map<String, String> params = new TreeMap<>();
      params.put("method", "flickr.auth.oauth.checkToken");
      params.put("oauth_token", oauthToken);
  
      return jinx.flickrGet(params, OAuthCredentials.class);
    }
docs: Returns the credentials attached to an OAuth authentication token.
  
  @param oauthToken the oauth token.
  @return credentials attached to the oauth token.
  @throws JinxException if there are any errors, or if the oauthToken is null.
  @see <a href="https://www.flickr.com/services/api/flickr.auth.oauth.checkToken.html">flickr.auth.oauth.checkToken</a>