code: def _test_autocorr(self, pdf):
      psdf = ps.from_pandas(pdf)
      for lag in range(-10, 10):
          p_autocorr = pdf["s1"].autocorr(lag)
          ps_autocorr = psdf["s1"].autocorr(lag)
          self.assert_eq(p_autocorr, ps_autocorr, almost=True)
  
imports: import unittest
  from decimal import Decimal
  import numpy
  import pandas
  from pyspark import pandas
  from pyspark.testing.pandasutils import ComparisonTestBase
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 21 for calling the SeriesStatMixin obj's underlying member method code with example usage: obj._test_autocorr(pdf) without return types