code: def test_prior_mode(self):
      train_data = self.create_test_data()
      likelihood, labels = self.create_likelihood_and_labels()
      prior_model = self.create_model(None, None, likelihood)
      model = self.create_model(train_data, labels, likelihood)
      prior_model.eval()
      model.eval()
  
      test_data = self.create_test_data()
      prior_out = prior_model(test_data)
      with gpytorch.settings.prior_mode(True):
          prior_out_cm = model(test_data)
      self.assertTrue(torch.allclose(prior_out.mean, prior_out_cm.mean))
      self.assertTrue(
          torch.allclose(
              prior_out.covariance_matrix,
              prior_out_cm.covariance_matrix,
          )
      )
  
imports: import unittest
  import torch
  import gpytorch
  from gpytorch import settings
  from gpytorch.kernels import GridInterpolationKernel
  from gpytorch.likelihoods import GaussianLikelihood
  from gpytorch.mlls import ExactMarginalLogLikelihood
  from gpytorch.models import ExactGP
  from gpytorch.models.exact_prediction_strategies import InterpolatedPredictionStrategy
  from gpytorch.test.model_test_case import BaseModelTestCase
label_desc: Use image node_id 11 for calling the TestExactGP obj's underlying member method code with example usage: obj.test_prior_mode() without return types