join(question, draft) -> join([question, draft])

examples/runnable-pregel.py

@@ -98,7 +98,7 @@ editor = (
 reviser = (
     # subscribe to new values of "notes" channel,
     # and join them with the current values of "question" and "draft"
-    Pregel.subscribe_to(["notes"]).join("question", "draft")
+    Pregel.subscribe_to(["notes"]).join(["question", "draft"])
     | reviser_chain
     | Pregel.send_to("draft")
 )

permchain/pregel.py

@@ -101,7 +101,7 @@ class PregelInvoke(RunnableBinding):
 
     kwargs: Mapping[str, Any] = Field(default_factory=dict)
 
-    def join(self, *channels: str) -> PregelInvoke:
+    def join(self, channels: Sequence[str]) -> PregelInvoke:
         joiner = RunnablePassthrough.assign(
             **{chan: PregelRead(chan) for chan in channels}
         )