Conform to PEP8

Author: dbeniamine

pandas/tests/groupby/test_grouping.py

@@ -153,12 +153,12 @@ def test_grouper_period_index(self):
         # GH 32108
         periods = 2
         index = pd.period_range(start="2018-01", periods=periods, freq="M")
-        periodSerie = pd.Series(range(periods), index=index)
-        periodSerie.index.name = "Month"
-        result = periodSerie.groupby(periodSerie.index.month).sum()
+        period_serie = pd.Series(range(periods), index=index)
+        period_serie.index.name = "Month"
+        result = period_serie.groupby(period_serie.index.month).sum()
 
         expected = pd.Series(range(0, periods), index=range(1, periods + 1))
-        expected.index.name = periodSerie.index.name
+        expected.index.name = period_serie.index.name
         tm.assert_series_equal(result, expected)
 
     def test_grouper_multilevel_freq(self):