code: def test_methylation_coefficients(self):
      rslt = self.meth_fit
      assert_close(
          rslt.params[:-2], expected_methylation_mean["Estimate"], 1e-2
      )
      assert_close(
          rslt.tvalues[:-2], expected_methylation_mean["zvalue"], 0.1
      )
      assert_close(
          rslt.pvalues[:-2], expected_methylation_mean["Pr(>|z|)"], 1e-2
      )
  
imports: import io
  import os
  import pytest
  import numpy
  from numpy.testing import assert_allclose, assert_equal
  import pandas
  import patsy
  from statsmodels.api import families
  from statsmodels.tools.sm_exceptions import ValueWarning
  from statsmodels.othermod.betareg import BetaModel
  from .results import results_betareg
label_desc: Use image node_id 4 for calling the TestBetaModel obj's underlying member method code with example usage: obj.test_methylation_coefficients() without return types