style: use *_args and **_kwargs

xmodule/library_content_block.py

@@ -590,9 +590,9 @@ def children_are_syncing(self, request, suffix=''):  # pylint: disable=unused-ar
     def studio_post_duplicate(
         self,
         source_item,
-        *_,
-        **__,
-    ) -> None:  # pylint: disable=unused-argument
+        *_args,
+        **__kwargs,
+    ) -> None:
         """
         Used by the studio after basic duplication of a source block. We handle the children
         ourselves, because we have to properly reference the library upstream and set the overrides.
@@ -601,7 +601,6 @@ def studio_post_duplicate(
         """
         self._validate_sync_permissions()
         self.get_tools(to_read_library_content=True).trigger_duplication(source_block=source_item, dest_block=self)
-        return True  # Children have been handled.
 
     def _validate_library_version(self, validation, lib_tools, version, library_key):
         """