code: def _encrypted_data_keys_hash(hasher, encrypted_data_keys):
      hashed_keys = []
      for edk in encrypted_data_keys:
          serialized_edk = serialize_encrypted_data_key(edk)
          _hasher = hasher.copy()
          _hasher.update(serialized_edk)
          hashed_keys.append(_hasher.finalize())
      return b"".join(sorted(hashed_keys))