docstr: Tests that validity of the tune setting is checked
docstr_tok: ["Tests","that","validity","of","the","tune","setting","is","checked"]
code: def test_demcmc_tune_parameter(self):
      """Tests that validity of the tune setting is checked"""
      with pm.Model() as model:
          pm.Normal("n", mu=0, sigma=1, size=(2, 3))
  
          step = DEMetropolis()
          assert step.tune == "scaling"
  
          step = DEMetropolis(tune=None)
          assert step.tune is None
  
          step = DEMetropolis(tune="scaling")
          assert step.tune == "scaling"
  
          step = DEMetropolis(tune="lambda")
          assert step.tune == "lambda"
  
          with pytest.raises(ValueError):
              DEMetropolis(tune="foo")
  
imports: import warnings
  import arviz
  import numpy
  import numpy.testing
  import pytensor
  import pytest
  import pymc
  from pymc.step_methods.metropolis import BinaryGibbsMetropolis, CategoricalGibbsMetropolis, DEMetropolis, DEMetropolisZ, Metropolis, MultivariateNormalProposal, NormalProposal
  from pymc.testing import fast_unstable_sampling_mode
  from tests import sampler_fixtures
  from tests.helpers import RVsAssignmentStepsTester, StepMethodTester
  from tests.models import mv_simple, mv_simple_discrete, simple_categorical
label_desc: Use image node_id 1 for calling the TestDEMetropolis obj's underlying member method code with example usage: obj.test_demcmc_tune_parameter() without return types