code: def test_weightstats_len_1():
      x1 = [1]
      w1 = [1]
      d1 = DescrStatsW(x1, w1)
      assert (d1.quantile([0.0, 0.5, 1.0]) == 1).all()
  
imports: import numpy
  from scipy import stats
  import pandas
  from numpy.testing import assert_, assert_almost_equal, assert_allclose
  from statsmodels.stats.weightstats import DescrStatsW, CompareMeans, ttest_ind, ztest, zconfint
  from statsmodels.tools.testing import Holder
label_desc: Use image node_id 3 for calling a global function with example usage: test_weightstats_len_1() without return types