Fixed PeriodArray._time_shift positional argument (#24524)

Author: TomAugspurger

pandas/core/arrays/period.py

@@ -418,7 +418,7 @@ def fillna(self, value=None, method=None, limit=None):
 
     # --------------------------------------------------------------------
 
-    def _time_shift(self, n, freq=None):
+    def _time_shift(self, periods, freq=None):
         """
         Shift each value by `periods`.
 
@@ -437,7 +437,7 @@ def _time_shift(self, n, freq=None):
             raise TypeError("`freq` argument is not supported for "
                             "{cls}._time_shift"
                             .format(cls=type(self).__name__))
-        values = self.asi8 + n * self.freq.n
+        values = self.asi8 + periods * self.freq.n
         if self._hasnans:
             values[self._isnan] = iNaT
         return type(self)(values, freq=self.freq)