code: def test_constraint(self):
      mean = self.create_mean()
      self.assertAllClose(
          mean.constant, torch.zeros(mean.constant.shape)
      )
  
      constraint = GreaterThan(1.5)
      mean = self.create_mean(constraint=constraint)
      self.assertTrue(torch.all(mean.constant >= 1.5))
      mean.constant = torch.full(
          self.__class__.batch_shape or torch.Size([]), fill_value=1.65
      )
      self.assertAllClose(
          mean.constant, torch.tensor(1.65).expand(mean.constant.shape)
      )
  
imports: import math
  import pickle
  import unittest
  import warnings
  from collections import OrderedDict
  import torch
  import gpytorch
  from gpytorch.constraints import GreaterThan
  from gpytorch.means import ConstantMean
  from gpytorch.priors import NormalPrior
  from gpytorch.test.base_mean_test_case import BaseMeanTestCase
  from gpytorch.utils.warnings import OldVersionWarning
label_desc: Use image node_id 3 for calling the TestConstantMean obj's underlying member method code with example usage: obj.test_constraint() without return types