code: def test_is_unique(self):
      # We can't use pandas' is_unique for comparison. pandas 0.23 ignores None
      pser = pd.Series([1, 2, 2, None, None])
      psser = ps.from_pandas(pser)
      self.assertEqual(False, psser.is_unique)
      self.assertEqual(False, (psser + 1).is_unique)
  
      pser = pd.Series([1, None, None])
      psser = ps.from_pandas(pser)
      self.assertEqual(False, psser.is_unique)
      self.assertEqual(False, (psser + 1).is_unique)
  
      pser = pd.Series([1])
      psser = ps.from_pandas(pser)
      self.assertEqual(pser.is_unique, psser.is_unique)
      self.assertEqual((pser + 1).is_unique, (psser + 1).is_unique)
  
      pser = pd.Series([1, 1, 1])
      psser = ps.from_pandas(pser)
      self.assertEqual(pser.is_unique, psser.is_unique)
      self.assertEqual((pser + 1).is_unique, (psser + 1).is_unique)
  
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 5 for calling the SeriesStatMixin obj's underlying member method code with example usage: obj.test_is_unique() without return types