code: def test_default_names(self):
      input_data = {
          "img": np.array([[0, 1], [1, 2]]),
          "seg": np.array([[3, 4], [4, 5]]),
      }
      result = CopyItemsd(keys=["img", "seg"], times=2, names=None)(
          input_data
      )
      for name in ["img_0", "seg_0", "img_1", "seg_1"]:
          self.assertTrue(name in result)
  
file_path: MONAI/tests/test_copy_itemsd.py
imports: from __future__ import annotations
  import unittest
  import numpy
  import torch
  from parameterized import parameterized
  from monai.networks import eval_mode
  from monai.transforms import CopyItemsd
  from monai.utils import ensure_tuple
  from tests.utils import assert_allclose
label_desc: Use image node_id 2 for calling the TestCopyItemsd obj's underlying member method code with example usage: obj.test_default_names() without return types