code: public Response leave(String groupId, boolean deletePhotos) throws JinxException {
      JinxUtils.validateParams(groupId);
      Map<String, String> params = new TreeMap<>();
      params.put("method", "flickr.groups.leave");
      params.put("group_id", groupId);
      if (deletePhotos) {
        params.put("delete_photos", "true");
      }
      return jinx.flickrPost(params, Response.class);
    }
docs: Leave a group.
  <br>
  If the user is the only administrator left, and there are other members,
  the oldest member will be promoted to administrator.
  <br>
  If the user is the last person in the group, the group will be deleted.
  <br>
  This method requires authentication with 'delete' permission.
  <br>
  
  @param groupId      (Required) The NSID of the Group to leave.
  @param deletePhotos Delete all photos by this user from the group.
  @return object with response from Flickr indicating ok or fail.
  @throws JinxException if required parameters are missing, or if there are any errors.
  @see <a href="https://www.flickr.com/services/api/flickr.groups.leave.html">flickr.groups.leave</a>