code: def test_ModelListGP_single(self):
      tkwargs = {"device": self.device, "dtype": torch.float}
      train_x1, train_y1 = _get_random_data(
          batch_shape=torch.Size(), m=1, n=10, **tkwargs
      )
      model1 = SingleTaskGP(train_X=train_x1, train_Y=train_y1)
      model = ModelListGP(model1)
      model.to(**tkwargs)
      test_x = torch.tensor([[0.25], [0.75]], **tkwargs)
      posterior = model.posterior(test_x)
      self.assertIsInstance(posterior, GPyTorchPosterior)
      self.assertIsInstance(posterior.distribution, MultivariateNormal)
  
imports: import itertools
  import warnings
  from copy import deepcopy
  from typing import Optional
  import torch
  from botorch.acquisition.objective import ScalarizedPosteriorTransform
  from botorch.exceptions.errors import BotorchTensorDimensionError
  from botorch.exceptions.warnings import OptimizationWarning
  from botorch.fit import fit_gpytorch_mll
  from botorch.models.gp_regression import SingleTaskGP
  from botorch.models.model_list_gp_regression import ModelListGP
  from botorch.models.multitask import MultiTaskGP
  from botorch.models.transforms.input import Normalize
  from botorch.models.transforms.outcome import ChainedOutcomeTransform, Log, Standardize
  from botorch.posteriors import GPyTorchPosterior, PosteriorList, TransformedPosterior
  from botorch.sampling.base import MCSampler
  from botorch.sampling.list_sampler import ListSampler
  from botorch.sampling.normal import IIDNormalSampler
  from botorch.utils.testing import _get_random_data, BotorchTestCase
  from gpytorch.distributions import MultitaskMultivariateNormal, MultivariateNormal
  from gpytorch.kernels import MaternKernel, ScaleKernel
  from gpytorch.likelihoods import LikelihoodList
  from gpytorch.likelihoods.gaussian_likelihood import FixedNoiseGaussianLikelihood, GaussianLikelihood
  from gpytorch.means import ConstantMean
  from gpytorch.mlls import SumMarginalLogLikelihood
  from gpytorch.mlls.exact_marginal_log_likelihood import ExactMarginalLogLikelihood
  from gpytorch.priors import GammaPrior
  from torch import Tensor
label_desc: Use image node_id 4 for calling the TestModelListGP obj's underlying member method code with example usage: obj.test_ModelListGP_single() without return types