Series mask method's "other" parameter does not accept pandas.NA (#725)

* Update series.pyi

* Add type tests for mark

* Use np.integer instead of np.int64

Author: ABizzinotto

pandas-stubs/core/series.pyi

@@ -1378,7 +1378,7 @@ class Series(IndexOpsMixin, NDFrame, Generic[S1]):
     def mask(
         self,
         cond: MaskType,
-        other: Scalar | Series[S1] | DataFrame | Callable = ...,
+        other: Scalar | Series[S1] | DataFrame | Callable | NAType | None = ...,
         *,
         inplace: _bool = ...,
         axis: AxisIndex | None = ...,

tests/test_series.py

@@ -2017,3 +2017,20 @@ def test_to_string() -> None:
         ),
         str,
     )
+
+
+def test_types_mask() -> None:
+    s = pd.Series([1, 2, 3, 4, 5])
+
+    # Test case with a boolean condition and a scalar value
+    check(assert_type(s.mask(s > 3, 10), pd.Series), pd.Series, np.integer)
+
+    # Test case with a boolean condition and a callable
+    def double(x):
+        return x * 2
+
+    check(assert_type(s.mask(s > 3, double), pd.Series), pd.Series, np.integer)
+
+    # Test cases with None and pd.NA as other
+    check(assert_type(s.mask(s > 3, None), pd.Series), pd.Series, np.float64)
+    check(assert_type(s.mask(s > 3, pd.NA), pd.Series), pd.Series, np.float64)