GH1226 PR Feedback

Author: loicdiridollou

pandas-stubs/io/formats/style.pyi

@@ -53,6 +53,13 @@ class _DataFrameFunc(Protocol):
         self, series: DataFrame, /, *args: Any, **kwargs: Any
     ) -> npt.NDArray | DataFrame: ...
 
+class _MapCallable(Protocol):
+    """Dedicated signature for functions passed in Styler.map."""
+
+    def __call__(
+        self, first_arg: Scalar, /, *args: Any, **kwargs: Any
+    ) -> str | None: ...
+
 class Styler(StylerRenderer):
     def __init__(
         self,
@@ -80,7 +87,7 @@ class Styler(StylerRenderer):
     @overload
     def map(
         self,
-        func: Callable[..., str | None],
+        func: _MapCallable,
         subset: Subset | None = ...,
         **kwargs: Any,
     ) -> Styler: ...

tests/test_styler.py

@@ -247,7 +247,7 @@ def test_styler_map() -> None:
         Styler,
     )
 
-    def color_negative(v: Scalar, color: str) -> str | None:
+    def color_negative(v: Scalar, /, color: str) -> str | None:
         return f"color: {color};" if isinstance(v, float) and v < 0 else None
 
     df = DataFrame(np.random.randn(5, 2), columns=["A", "B"])