code: def _validate_bag(self, bag, **kwargs):
          
          failed = None
          try:
              bag.validate(**kwargs)
          except BagValidationError as e:
              failed = e
              #  for d in e.details:
              #      if isinstance(d, ChecksumMismatch):
              #          log.error("Validation Error: expected %s to have %s checksum of %s but found %s", d.path, d.algorithm, d.expected, d.found)
              #      else:
              #          log.error("Validation Error: %s", d)
          if failed:
              raise BagValidationError("%s" % failed)
docs: Validate BagIt (checksums, payload.oxum etc)