docs: def prune_old(self):
          """
          Removes the directories that are older than a certain date.
          """
          path = self.pubdir
          dirmask = self.dirmask
          expire = self.expire
          expire_limit = int(time.time()) - (86400 * expire)
  
          logger.info('Pruning directories older than %d days', expire)
  
          if not os.path.isdir(path):
              logger.warning('Dir %r not found -- skipping pruning', path)
              return
  
          for entry in os.listdir(path):
              logger.debug('Found: %r', entry)
              if os.path.isdir(os.path.join(path, entry)):
                  try: 
                      stamp = time.mktime(time.strptime(entry, dirmask))
                  except ValueError as e:
                      logger.info('Dir %r did not match dirmask %r: %r', entry, dirmask, e)
                      logger.info('Skipping %r', entry)
                      continue
  
                  if stamp < expire_limit:
                      shutil.rmtree(os.path.join(path, entry))
                      logger.info('File Publisher: Pruned old dir: %r', entry)
                  else:
                      logger.info('%r is still active', entry)
              else:
                  logger.info('%r is not a directory. Skipping.', entry)
  
          logger.info('Finished with pruning')