code: def test_pickle_approx(three_var_approx):
      import cloudpickle
  
      dump = cloudpickle.dumps(three_var_approx)
      new = cloudpickle.loads(dump)
      assert new.sample(1)
  
imports: import functools
  import numpy
  import pytensor.tensor
  import pytest
  import pymc
  from pymc.variational import opvi
  from pymc.variational.approximations import Empirical, EmpiricalGroup, FullRank, FullRankGroup, MeanField, MeanFieldGroup
  from tests.helpers import not_raises
label_desc: Use image node_id 10 for calling a global function with example usage: test_pickle_approx(three_var_approx) without return types