diff --git a/spanner_orm/model.py b/spanner_orm/model.py
index 2269fe7..c2cf0ee 100644
--- a/spanner_orm/model.py
+++ b/spanner_orm/model.py
@@ -17,22 +17,24 @@
 import copy
 from typing import Any, Callable, Dict, Iterable, List, Optional, Type, TypeVar, Union
 
-from spanner_orm import api
-from spanner_orm import condition
-from spanner_orm import error
-from spanner_orm import foreign_key_relationship
-from spanner_orm import field
-from spanner_orm import index
-from spanner_orm import metadata
-from spanner_orm import query
-from spanner_orm import registry
-from spanner_orm import relationship
-from spanner_orm import table_apis
-
 from google.api_core import exceptions
 from google.cloud import spanner
 from google.cloud.spanner_v1 import transaction as spanner_transaction
 
+from spanner_orm import (
+  api,
+  condition,
+  error,
+  field,
+  foreign_key_relationship,
+  index,
+  metadata,
+  query,
+  registry,
+  relationship,
+  table_apis,
+)
+
 T = TypeVar('T')
 
 
@@ -684,7 +686,7 @@ def delete(
     else:
       self.spanner_api().run_write(db_api, *args)
 
-  def id(self) -> Dict[str, Any]:
+  def _id(self) -> Dict[str, Any]:
     """Gets the identifier of this object.
 
     Returns:
@@ -710,7 +712,7 @@ def reload(
       in Spanner, or None if no information was found (object was deleted or
       never was persisted)
     """
-    updated_object = self._metaclass.find(transaction=transaction, **self.id())
+    updated_object = self._metaclass.find(transaction=transaction, **self._id())
     if updated_object is None:
       return None
     start_values = {}
@@ -746,7 +748,7 @@ def save(
     if self._persisted:
       changed_values = self.changes()
       if changed_values:
-        changed_values.update(self.id())
+        changed_values.update(self._id())
         self._metaclass.update(transaction=transaction, **changed_values)
     else:
       self._metaclass.create(transaction=transaction, **self.values)
diff --git a/spanner_orm/tests/model_test.py b/spanner_orm/tests/model_test.py
index 1dc3c10..a7c28c7 100644
--- a/spanner_orm/tests/model_test.py
+++ b/spanner_orm/tests/model_test.py
@@ -15,15 +15,15 @@
 import logging
 import os
 import typing
-from typing import List
 import unittest
+from typing import List
 from unittest import mock
 
 from absl.testing import parameterized
 from google.api_core import exceptions
 from google.cloud import spanner
-from spanner_orm import error
-from spanner_orm import field
+
+from spanner_orm import error, field
 from spanner_orm.testlib.spanner_emulator import testlib as spanner_emulator_testlib
 from spanner_orm.tests import models
 
@@ -344,7 +344,7 @@ def test_id(self):
         'string_array': ['foo', 'bar']
     })
     test_model = models.UnittestModel(all_data)
-    self.assertEqual(test_model.id(), primary_key)
+    self.assertEqual(test_model._id(), primary_key)
 
   def test_changes(self):
     test_model = models.SmallTestModel({'key': 'key', 'value_1': 'value'})
@@ -412,7 +412,7 @@ def test_reload(self, find):
 
     find.return_value = None
     self.assertIsNone(model.reload())
-    find.assert_called_once_with(**model.id(), transaction=None)
+    find.assert_called_once_with(**model._id(), transaction=None)
 
   @mock.patch('spanner_orm.model.Model.find')
   def test_reload_reloads(self, find):