code: def likelihood() -> Likelihood:
      return Gaussian(variance=Setup.likelihood_variance)
  
imports: from typing import Any, Optional, Tuple
  import numpy
  import pytest
  import tensorflow
  from check_shapes import check_shapes
  import gpflow
  from gpflow import set_trainable
  from gpflow.config import default_float
  from gpflow.kernels import Kernel, SquaredExponential
  from gpflow.likelihoods import Gaussian, Likelihood
  from gpflow.models import GPR, SGPR, SVGP, VGP, BayesianModel
  from gpflow.optimizers import NaturalGradient
label_desc: Use image node_id 4 for calling a global function with example usage: likelihood() and returns: Gaussian