docs: def open_bag(dir_bag):
      """
      Open Bag at the given path
      :param str dir_bag: Path to Bag
      :return obj: Bag
      """
      logger_bagit.info("enter open_bag")
      try:
          bag = bagit.Bag(dir_bag)
          logger_bagit.info("opened bag")
          return bag
      except Exception as e:
          print("Error: failed to open bagit bag")
          logger_bagit.debug("failed to open bag, {}".format(e))
      return None