mark SyntaxError__str__ as METH_VARARGS
diff --git a/Python/exceptions.c b/Python/exceptions.c
index c585aa7..a656dbf 100644
--- a/Python/exceptions.c
+++ b/Python/exceptions.c
@@ -727,7 +727,7 @@
 
 PyMethodDef SyntaxError_methods[] = {
     {"__init__", SyntaxError__init__, 1},
-    {"__str__",  SyntaxError__str__,},
+    {"__str__",  SyntaxError__str__, 1},
     {NULL, NULL}
 };