code: def test_expand(self):
      usn = next(iter(self.distributions))
      # calling these lazy properties to cached them and
      #  hit associated branches in expand
      usn._orthogonalized_gauss
      usn.covariance_matrix
  
      other = usn.expand(torch.Size([2]))
      for key in ("loc", "covariance_matrix"):
          a = getattr(usn.gauss, key)
          self.assertTrue(
              all(
                  a.equal(b) for b in getattr(other.gauss, key).unbind()
              )
          )
  
      for key in (
          "loc",
          "covariance_matrix",
          "bounds",
          "log_partition",
      ):
          a = getattr(usn.trunc, key)
          self.assertTrue(
              all(
                  a.equal(b) for b in getattr(other.trunc, key).unbind()
              )
          )
  
      for b in other.cross_covariance_matrix.unbind():
          self.assertTrue(usn.cross_covariance_matrix.equal(b))
  
      fake_usn = deepcopy(usn)
      fake_usn.covariance_matrix = -1
      error_msg = (
          f"Type {type(-1)} of UnifiedSkewNormal's lazy property "
          "covariance_matrix not supported.*"
      )
      with self.assertRaisesRegex(TypeError, error_msg):
          other = fake_usn.expand(torch.Size([2]))
  
imports: from __future__ import annotations
  from copy import deepcopy
  from itertools import count
  from typing import Any, Dict, Optional, Sequence, Tuple
  import torch
  from botorch.utils.probability.mvnxpb import MVNXPB
  from botorch.utils.probability.truncated_multivariate_normal import TruncatedMultivariateNormal
  from botorch.utils.probability.unified_skew_normal import UnifiedSkewNormal
  from botorch.utils.testing import BotorchTestCase
  from linear_operator.operators import DenseLinearOperator
  from torch import Tensor
  from torch.distributions import MultivariateNormal
  from torch.special import ndtri
label_desc: Use image node_id 6 for calling the TestUnifiedSkewNormal obj's underlying member method code with example usage: obj.test_expand() without return types