replace assert with raise

narwhals-dev · Sep 15, 2024 · 9840e3c · 9840e3c
1 parent 60ed72e
commit 9840e3c
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/narwhals/_arrow/dataframe.py b/narwhals/_arrow/dataframe.py
@@ -183,7 +183,9 @@ def __getitem__(
 
             # PyArrow columns are always strings
             col_name = item[1] if isinstance(item[1], str) else self.columns[item[1]]
-            assert not isinstance(item[0], str)  # help mypy  # noqa: S101
+            if isinstance(item[0], str):
+                msg = "Can not slice with tuple with the first element as a str"  # pragma: no cover
+                raise TypeError(msg)  # pragma: no cover
             if (isinstance(item[0], slice)) and (item[0] == slice(None)):
                 return ArrowSeries(
                     self._native_frame[col_name],