diff --git a/py_gen/templates/_message_extra.py b/py_gen/templates/_message_extra.py
index 9fc2f5e..adfd0e7 100644
--- a/py_gen/templates/_message_extra.py
+++ b/py_gen/templates/_message_extra.py
@@ -32,8 +32,8 @@
 
 def parse_message(buf):
     msg_ver, msg_type, msg_len, msg_xid = parse_header(buf)
-    if msg_ver != const.OFP_VERSION and msg_type != const.OFPT_HELLO:
-        raise loxi.ProtocolError("wrong OpenFlow version (expected %d, got %d)" % (const.OFP_VERSION, msg_ver))
+    if msg_ver != ofp.OFP_VERSION and msg_type != ofp.OFPT_HELLO:
+        raise loxi.ProtocolError("wrong OpenFlow version (expected %d, got %d)" % (ofp.OFP_VERSION, msg_ver))
     if len(buf) != msg_len:
         raise loxi.ProtocolError("incorrect message size")
     return message.unpack(loxi.generic_util.OFReader(buf))