code: def test_flat_path(self):
      key1 = fake_cloud_client.FakeDatastoreKey("abc", "1")
      self.assertTupleEqual(("abc", "1"), key1.flat_path)
      key2 = fake_cloud_client.FakeDatastoreKey(
          "def", "xyz", parent=key1
      )
      self.assertTupleEqual(("abc", "1", "def", "xyz"), key2.flat_path)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  from io import BytesIO
  import unittest
  from eval_lib.tests import fake_cloud_client
  from six import assertCountEqual
  from six import b
label_desc: Use image node_id 1 for calling the FakeDatastoreKeyTest obj's underlying member method code with example usage: obj.test_flat_path() without return types