contains

Author: MarcoGorelli

pandas-stubs/core/indexes/period.pyi

@@ -36,6 +36,7 @@ class PeriodIndex(DatetimeIndexOpsMixin[pd.Period, np.object_], PeriodIndexField
     ): ...
     @property
     def values(self) -> npt.NDArray[np.object_]: ...
+    def __contains__(self, key: object) -> bool: ...
     @overload
     def __sub__(self, other: Period) -> Index: ...
     @overload

tests/test_indexes.py

@@ -1502,3 +1502,9 @@ def test_period_index_constructor() -> None:
         ),
         pd.PeriodIndex,
     )
+
+
+def test_period_index_contains() -> None:
+    pidx = pd.PeriodIndex(["2000"], freq="D")
+    check(assert_type("2000" in pidx, bool), bool)
+    check(assert_type(42 in pidx, bool), bool)