code: public UserUrls lookupUser(String url) throws JinxException {
      JinxUtils.validateParams(url);
      Map<String, String> params = new TreeMap<>();
      params.put("method", "flickr.urls.lookupUser");
      params.put("url", url);
      return jinx.flickrGet(params, UserUrls.class);
    }
docs: Returns a user NSID, given the url to a user's photos or profile.
  
  This method does not require authentication.
  
  @param url url to the user's profile or photos page. Required.
  @return user id and username.
  @throws JinxException if there are any errors.
  @see <a href="https://www.flickr.com/services/api/flickr.urls.lookupUser.html">flickr.urls.lookupUser</a>