lint

py-polars/polars/dataframe/frame.py

@@ -1264,7 +1264,7 @@ def __deepcopy__(self, memo: None = None) -> DataFrame:
     def _ipython_key_completions_(self) -> list[str]:
         return self.columns
 
-    def __arrow_c_stream__(self, requested_schema: object):
+    def __arrow_c_stream__(self, requested_schema: object) -> object:
         """
         Export a DataFrame via the Arrow PyCapsule Interface.
 

py-polars/polars/series/series.py

@@ -1401,7 +1401,7 @@ def __array_ufunc__(
             )
             raise NotImplementedError(msg)
 
-    def __arrow_c_stream__(self, requested_schema: object):
+    def __arrow_c_stream__(self, requested_schema: object) -> object:
         """
         Export a Series via the Arrow PyCapsule Interface.
 

py-polars/tests/unit/interop/test_interop.py

@@ -762,12 +762,12 @@ class PyCapsuleStreamHolder:
         used.
         """
 
-        capsule: tuple[object, object]
+        capsule: object
 
-        def __init__(self, capsule: tuple[object, object]):
+        def __init__(self, capsule: object) -> None:
             self.capsule = capsule
 
-        def __arrow_c_stream__(self, requested_schema) -> tuple[object, object]:
+        def __arrow_c_stream__(self, requested_schema: object) -> object:
             return self.capsule
 
     df = pl.DataFrame({"a": [1, 2, 3], "b": ["a", "b", "c"]})
@@ -776,4 +776,5 @@ def __arrow_c_stream__(self, requested_schema) -> tuple[object, object]:
     assert df.schema.names() == out.schema.names
 
     df2 = pl.from_arrow(out)
-    assert df.equals(df2)  # type: ignore
+    assert isinstance(df2, pl.DataFrame)
+    assert df.equals(df2)

py-polars/tests/unit/series/test_series.py

@@ -639,12 +639,12 @@ class PyCapsuleSeriesHolder:
         used.
         """
 
-        capsule: tuple[object, object]
+        capsule: object
 
-        def __init__(self, capsule: tuple[object, object]):
+        def __init__(self, capsule: object):
             self.capsule = capsule
 
-        def __arrow_c_stream__(self, requested_schema: object) -> tuple[object, object]:
+        def __arrow_c_stream__(self, requested_schema: object) -> object:
             return self.capsule
 
     a = pl.Series("a", [1, 2, 3, None])