code: def test_cardinality(self, batch_size, kernel_size, device, dtype):
      inp = torch.zeros(batch_size, 3, 4, 4, device=device, dtype=dtype)
      blur = BoxBlur(kernel_size)
      actual = blur(inp)
      expected = (batch_size, 3, 4, 4)
      assert actual.shape == expected
  
file_path: kornia/test/filters/test_blur.py
imports: import pytest
  import torch
  from kornia.filters import BoxBlur, box_blur
  from kornia.testing import BaseTester, tensor_to_gradcheck_var
label_desc: Use image node_id 4 for calling the TestBoxBlur obj's underlying member method code with example usage: obj.test_cardinality(batch_size, kernel_size, device, dtype) without return types