code: def test_mc_error(self, size, batches, ndim, circular):
      x = np.random.randn(
          size, ndim
      ).squeeze()  # pylint: disable=no-member
      assert (
          _mc_error(x, batches=batches, circular=circular) is not None
      )
  
imports: import os
  import numpy
  import packaging
  import pandas
  import pytest
  import scipy
  from numpy.testing import assert_almost_equal
  from ...data import from_cmdstan, load_arviz_data
  from ...rcparams import rcParams
  from ...sel_utils import xarray_var_iter
  from ...stats import bfmi, ess, mcse, rhat
  from ...stats.diagnostics import _ess, _ess_quantile, _mc_error, _mcse_quantile, _multichain_statistics, _rhat, _rhat_rank, _split_chains, _z_scale, ks_summary
label_desc: Use image node_id 27 for calling the TestDiagnostics obj's underlying member method code with example usage: obj.test_mc_error(size, batches, ndim, circular) without return types