code: def test_at_time(self):
      idx = pd.date_range("2018-04-09", periods=4, freq="1D20min")
      pser = pd.Series([1, 2, 3, 4], index=idx)
      psser = ps.from_pandas(pser)
      self.assert_eq(
          pser.at_time("0:20").sort_index(),
          psser.at_time("0:20").sort_index(),
      )
  
      pser.index.name = "ts"
      psser = ps.from_pandas(pser)
      self.assert_eq(
          pser.at_time("0:20").sort_index(),
          psser.at_time("0:20").sort_index(),
      )
  
      pser.index.name = "index"
      psser = ps.from_pandas(pser)
      self.assert_eq(
          pser.at_time("0:20").sort_index(),
          psser.at_time("0:20").sort_index(),
      )
  
imports: import unittest
  from itertools import product
  import numpy
  import pandas
  from pyspark import pandas
  from pyspark.errors import PySparkValueError
  from pyspark.testing.pandasutils import ComparisonTestBase
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 19 for calling the SeriesComputeMixin obj's underlying member method code with example usage: obj.test_at_time() without return types