Add types.PeriodFrequency

Exactly as in pandas-dev/pandas-stubs#1394.

Author: khaeru

sdmx/types.py

@@ -1,9 +1,38 @@
 from typing import TypedDict
 
+from pandas.tseries.offsets import (
+    Day,
+    Hour,
+    Micro,
+    Milli,
+    Minute,
+    MonthEnd,
+    Nano,
+    QuarterEnd,
+    Second,
+    Week,
+    YearEnd,
+)
+
 from sdmx.convert.pandas import Attributes
 from sdmx.format.csv.common import CSVFormatOptions
 from sdmx.model.common import Agency
 
+# See https://github.com/pandas-dev/pandas-stubs/pull/1394#issuecomment-3356958356
+PeriodFrequency = (
+    Day
+    | Hour
+    | Minute
+    | Second
+    | Milli
+    | Micro
+    | Nano
+    | YearEnd
+    | QuarterEnd
+    | MonthEnd
+    | Week
+)
+
 
 class VersionableArtefactArgs(TypedDict, total=False):
     version: str