Add issue references

Author: craustin

pandas/tseries/frequencies.py

@@ -935,6 +935,7 @@ def _get_wom_rule(self):
             return None
 
         week_of_months = unique((self.index.day - 1) // 7)
+        # Only attempt to infer up to WOM-4. See #9425
         week_of_months = week_of_months[week_of_months < 4]
         if len(week_of_months) == 0 or len(week_of_months) > 1:
             return None

pandas/tseries/tests/test_frequencies.py

@@ -214,10 +214,12 @@ def test_week_of_month(self):
             self._check_generated_range('1/1/2000', 'WOM-%d%s' % (i, day))
 
     def test_fifth_week_of_month(self):
+        # Only supports freq up to WOM-4. See #9425
         func = lambda: date_range('2014-01-01', freq='WOM-5MON')
         self.assertRaises(ValueError, func)
 
     def test_fifth_week_of_month_infer(self):
+        # Only attempts to infer up to WOM-4. See #9425
         index = DatetimeIndex(["2014-03-31", "2014-06-30", "2015-03-30"])
         assert frequencies.infer_freq(index) is None