fix bind arg
diff --git a/Demo/sockets/mcast.py b/Demo/sockets/mcast.py
index 4011383..8c6298e 100755
--- a/Demo/sockets/mcast.py
+++ b/Demo/sockets/mcast.py
@@ -73,7 +73,7 @@
 	s.setsockopt(SOL_SOCKET, SO_REUSEPORT, 1)
 	#
 	# Bind it to the port
-	s.bind('', port)
+	s.bind(('', port))
 	#
 	# Look up multicast group address in name server
 	# (doesn't hurt if it is already in ddd.ddd.ddd.ddd format)