code: def test_proportion_effect_size():
      # example from blog
      es = smprop.proportion_effectsize(0.5, 0.4)
      assert_almost_equal(es, 0.2013579207903309, decimal=13)
  
imports: import warnings
  import numpy
  from numpy.testing import assert_allclose, assert_almost_equal, assert_array_less, assert_equal, assert_raises
  import pandas
  import pytest
  import statsmodels.stats.proportion
  from statsmodels.stats.proportion import confint_proportions_2indep, multinomial_proportions_confint, power_proportions_2indep, proportion_confint, samplesize_proportions_2indep_onetail, score_test_proportions_2indep
  from statsmodels.tools.sm_exceptions import HypothesisTestWarning
  from statsmodels.tools.testing import Holder
  from statsmodels.stats.tests.results.results_proportion import res_binom, res_binom_methods
label_desc: Use image node_id 4 for calling a global function with example usage: test_proportion_effect_size() without return types