code: def test_stat_functions_multiindex_column(self):
      arrays = [
          np.array(["A", "A", "B", "B"]),
          np.array(["one", "two", "one", "two"]),
      ]
      pdf = pd.DataFrame(
          np.random.randn(3, 4), index=["A", "B", "C"], columns=arrays
      )
      psdf = ps.from_pandas(pdf)
      self._test_stat_functions(pdf.A, psdf.A)
      self._test_stat_functions(pdf, psdf)
  
imports: import numpy
  import pandas
  from pyspark import pandas
  from pyspark.testing.pandasutils import PandasOnSparkTestCase, SPARK_CONF_ARROW_ENABLED
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 3 for calling the StatsTestsMixin obj's underlying member method code with example usage: obj.test_stat_functions_multiindex_column() without return types