code: def _get_test_posterior(device, dtype=torch.float):
      mean = torch.zeros(2, device=device, dtype=dtype)
      cov = torch.eye(2, device=device, dtype=dtype)
      mvn = MultivariateNormal(mean, cov)
      return GPyTorchPosterior(mvn)
  
file_path: botorch/test/sampling/test_normal.py
imports: import torch
  from botorch.exceptions.errors import UnsupportedError
  from botorch.posteriors import GPyTorchPosterior
  from botorch.sampling.normal import IIDNormalSampler, NormalMCSampler, SobolQMCNormalSampler
  from botorch.utils.testing import BotorchTestCase
  from gpytorch.distributions import MultivariateNormal
  from linear_operator.operators import DiagLinearOperator
label_desc: Use image node_id 1 for calling a global function with example usage: _get_test_posterior(device, dtype) and returns: GPyTorchPosterior