code: def test_invertible_init(self, D=5):
      mu = torch.randn(D)
      cov = torch.randn(D, D).tril_()
      dist = MultivariateNormal(
          mu, CholLinearOperator(TriangularLinearOperator(cov))
      )
  
      v_dist = NaturalVariationalDistribution(D, mean_init_std=0.0)
      v_dist.initialize_variational_distribution(dist)
  
      out_dist = v_dist()
  
      assert torch.allclose(
          out_dist.mean, dist.mean, rtol=1e-04, atol=1e-06
      )
      assert torch.allclose(
          out_dist.covariance_matrix, dist.covariance_matrix
      )
  
imports: import unittest
  import torch
  from linear_operator.operators import CholLinearOperator, TriangularLinearOperator
  import gpytorch
  from gpytorch.constraints import GreaterThan
  from gpytorch.distributions import MultivariateNormal
  from gpytorch.variational import NaturalVariationalDistribution, TrilNaturalVariationalDistribution
label_desc: Use image node_id 2 for calling the TestNatVariational obj's underlying member method code with example usage: obj.test_invertible_init(D) without return types