On Wed, 23 Aug 2023 12:41:56 +0100 Donald Hunter wrote:

+    def get_mcast_id(self, mcast_name, mcast_groups):
+        if mcast_name not in mcast_groups:
+            raise Exception(f'Multicast group "{mcast_name}" not present in the spec')
+        return mcast_groups[mcast_name].value
+

if you repost - missing extra empty line here

+class GenlProtocol(NetlinkProtocol):
+    def __init__(self, family_name):