def METHOD_NAME(self, url, urltype=None, content_type=None):
    if url is None:
        # do not add empty URL-s
        return
    urlobj = {"url": url}
    if urltype is not None:
        urlobj["type"] = urltype
    if content_type is not None:
        urlobj["content_type"] = content_type
    self._add_to_list_with_struct("link", urlobj)