docs: def ReadSignedBinaryReferences(
        self, binary_id,
        cursor=None):
      """Reads blob references for the signed binary with the given id."""
      cursor.execute(
          """
        SELECT blob_references, UNIX_TIMESTAMP(timestamp)
        FROM signed_binary_references
        WHERE binary_type = %s AND binary_path_hash = %s
      """, [
          binary_id.binary_type.SerializeToDataStore(),
          mysql_utils.Hash(binary_id.path)
      ])
      row = cursor.fetchone()
  
      if not row:
        raise db.UnknownSignedBinaryError(binary_id)
  
      raw_references, timestamp = row
      # TODO(hanuszczak): pytype does not understand overloads, so we have to cast
      # to a non-optional object.
      datetime = cast(rdfvalue.RDFDatetime,
                      mysql_utils.TimestampToRDFDatetime(timestamp))
  
      references = rdf_objects.BlobReferences.FromSerializedString(raw_references)
      return references, datetime