How to use the tink.proto.tink_pb2.EncryptedKeyset function in tink

def read_encrypted(self) -> tink_pb2.EncryptedKeyset:
    try:
      return json_format.Parse(self._serialized_keyset,
                               tink_pb2.EncryptedKeyset())
    except json_format.ParseError as e:
      raise tink_error.TinkError(e)

def read_encrypted(self) -> tink_pb2.EncryptedKeyset:
    if not self._serialized_keyset:
      raise tink_error.TinkError('No keyset found')
    try:
      encrypted_keyset = tink_pb2.EncryptedKeyset()
      encrypted_keyset.ParseFromString(self._serialized_keyset)
      return encrypted_keyset
    except message.DecodeError as e:
      raise tink_error.TinkError(e)

def write_encrypted(self, encrypted_keyset: tink_pb2.EncryptedKeyset) -> None:
    if not isinstance(encrypted_keyset, tink_pb2.EncryptedKeyset):
      raise tink_error.TinkError('invalid encrypted keyset.')
    self._io_stream.write(encrypted_keyset.SerializeToString())
    self._io_stream.flush()

def _encrypt(keyset: tink_pb2.Keyset,
             master_key_primitive: aead.Aead) -> tink_pb2.EncryptedKeyset:
  """Encrypts a Keyset and returns an EncryptedKeyset."""
  encrypted_keyset = master_key_primitive.encrypt(keyset.SerializeToString(),
                                                  b'')
  # Check if we can decrypt, to detect errors
  try:
    keyset2 = tink_pb2.Keyset.FromString(
        master_key_primitive.decrypt(encrypted_keyset, b''))
    if keyset != keyset2:
      raise tink_error.TinkError('cannot encrypt keyset: %s != %s' %
                                 (keyset, keyset2))
  except message.DecodeError:
    raise tink_error.TinkError('invalid keyset, corrupted key material')
  return tink_pb2.EncryptedKeyset(
      encrypted_keyset=encrypted_keyset, keyset_info=_keyset_info(keyset))