code: async def get_last_updated(self, source_id):
          
          last_updated = await self._db.get_last_updated(source_id)
          logger.info("LAST UPDATED: {} {}".format(last_updated, self))
          return last_updated
docs: Returns latest update-timestamp from storage for source.
  
          :param source_id: id of the source (source_id, ticker_id, blog_id pp)
          :type string:
          :returns: :py:class:`datetime.datetime` object of latest update datetime in db.