code: def test_symmetry_preserving(self, device, dtype):
      inp = torch.zeros(1, 1, 6, 6, device=device, dtype=dtype)
      inp[:, :, 2:4, 2:4] = 1.0
      pyr_out = kornia.geometry.PyrDown()(inp).squeeze()
      assert_close(pyr_out, pyr_out.flip(0))
      assert_close(pyr_out, pyr_out.flip(1))
  
imports: import pytest
  import torch
  from torch.autograd import gradcheck
  import kornia
  import kornia.testing
  from kornia.testing import BaseTester, assert_close
label_desc: Use image node_id 4 for calling the TestPyrDown obj's underlying member method code with example usage: obj.test_symmetry_preserving(device, dtype) without return types