diff --git a/ryu/ofproto/ofproto_v1_3_parser.py b/ryu/ofproto/ofproto_v1_3_parser.py
index a86addc3..bec72344 100644
--- a/ryu/ofproto/ofproto_v1_3_parser.py
+++ b/ryu/ofproto/ofproto_v1_3_parser.py
@@ -2766,7 +2766,7 @@ class OFPRoleRequest(MsgBase):
         self.role = role
         self.generation_id = generation_id
 
-    def __serialize_body(self):
+    def _serialize_body(self):
         assert self.role is not None
         assert self.generation_id is not None
         msg_pack_into(ofproto_v1_3.OFP_ROLE_REQUEST_PACK_STR,