Fix warning message

Author: Abacn

sdks/python/apache_beam/transforms/core.py

@@ -1520,12 +1520,12 @@ def _check_fn_use_yield_and_return(fn):
         has_return = True
         if lstripped_line.startswith(
             "return None") or lstripped_line.rstrip() == "return":
-          _LOGGER.warning(return_none_warning)
+          _LOGGER.warning(*return_none_warning)
       if has_yield and has_return:
         return True
 
     if not has_yield and not has_return:
-      _LOGGER.warning(return_none_warning)
+      _LOGGER.warning(*return_none_warning)
 
     return False
   except Exception as e: