code: def test_initialize_offset(self):
      kernel = DownsamplingKernel()
      kernel.initialize(offset=1)
      actual_value = torch.tensor(1.0).view_as(kernel.offset)
      self.assertLess(
          torch.linalg.norm(kernel.offset - actual_value), 1e-5
      )
  
imports: import torch
  from botorch.models.kernels.downsampling import DownsamplingKernel
  from botorch.utils.testing import BotorchTestCase
  from gpytorch.priors.torch_priors import GammaPrior, NormalPrior
  from gpytorch.test.base_kernel_test_case import BaseKernelTestCase
label_desc: Use image node_id 11 for calling the TestDownsamplingKernel obj's underlying member method code with example usage: obj.test_initialize_offset() without return types