Add a docstring note about before/after being mutually exclusive

davep · davep · commit 54bf7a9fd3e6 · 2022-11-14T16:56:37.000Z
diff --git a/src/textual/widget.py b/src/textual/widget.py
@@ -495,6 +495,10 @@ def move_child(
 
         Raises:
             WidgetError: If there is a problem with the child or target.
+
+        Note:
+            Only one of ``before`` or ``after`` can be provided. If neither
+            or both are provided a ``WidgetError`` will be raised.
         """
 
         # One or the other of before or after are required. Can't do
