diff --git a/piker/brokers/__init__.py b/piker/brokers/__init__.py
index 0c328d9f..94e4cbe1 100644
--- a/piker/brokers/__init__.py
+++ b/piker/brokers/__init__.py
@@ -98,13 +98,14 @@ async def open_cached_client(
     If one has not been setup do it and cache it.
 
     '''
-    brokermod = get_brokermod(brokername)
+    brokermod: ModuleType = get_brokermod(brokername)
+
+    # TODO: make abstract or `typing.Protocol`
+    # client: Client
     async with maybe_open_context(
         acm_func=brokermod.get_client,
         kwargs=kwargs,
-
     ) as (cache_hit, client):
-
         if cache_hit:
             log.runtime(f'Reusing existing {client}')