update Appender to doc in period.py

Author: HH-MWB

pandas/core/indexes/period.py

@@ -10,7 +10,7 @@
 from pandas._libs.tslibs.parsing import parse_time_string
 from pandas._libs.tslibs.period import Period
 from pandas._typing import DtypeObj, Label
-from pandas.util._decorators import Appender, cache_readonly
+from pandas.util._decorators import Appender, cache_readonly, doc
 
 from pandas.core.dtypes.common import (
     ensure_platform_int,
@@ -327,7 +327,7 @@ def _engine(self):
         period = weakref.ref(self)
         return self._engine_type(period, len(self))
 
-    @Appender(Index.__contains__.__doc__)
+    @doc(Index.__contains__)
     def __contains__(self, key: Any) -> bool:
         if isinstance(key, Period):
             if key.freq != self.freq:
@@ -405,7 +405,7 @@ def asof_locs(self, where, mask: np.ndarray) -> np.ndarray:
 
         return result
 
-    @Appender(Index.astype.__doc__)
+    @doc(Index.astype)
     def astype(self, dtype, copy=True, how="start"):
         dtype = pandas_dtype(dtype)