code: def versioned_bucket_lister(bucket, prefix='', delimiter='',
                              key_marker='', version_id_marker='', headers=None):
      
      more_results = True
      k = None
      while more_results:
          rs = bucket.get_all_versions(prefix=prefix, key_marker=key_marker,
                                       version_id_marker=version_id_marker,
                                       delimiter=delimiter, headers=headers,
                                       max_keys=999)
          for k in rs:
              yield k
          key_marker = rs.next_key_marker
          version_id_marker = rs.next_version_id_marker
          more_results= rs.is_truncated
docs: A generator function for listing versions in a bucket.