code: def test_neff(self):
      if hasattr(self, "min_n_eff"):
          with self.model:
              idata = to_inference_data(self.trace[self.burn :])
          n_eff = az.ess(idata)
          for var in n_eff:
              npt.assert_array_less(self.min_n_eff, n_eff[var])
  
imports: import arviz
  import numpy
  import numpy.testing
  import pytensor.tensor
  from scipy import stats
  import pymc
  from pymc.backends.arviz import to_inference_data
  from pymc.util import get_var_name
label_desc: Use image node_id 2 for calling the BaseSampler obj's underlying member method code with example usage: obj.test_neff() without return types