From f3291ca0f62ab988f17bac6fff808d1245465355 Mon Sep 17 00:00:00 2001
From: Nuno Campos <nuno@boringbits.io>
Date: Sun, 22 Oct 2023 19:41:11 +0100
Subject: [PATCH] Add back .join() method removed by accident

---
 permchain/pregel/read.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/permchain/pregel/read.py b/permchain/pregel/read.py
index d6d5eadbd..87399c78c 100644
--- a/permchain/pregel/read.py
+++ b/permchain/pregel/read.py
@@ -82,6 +82,15 @@ class PregelInvoke(RunnableBinding):
             **other_kwargs,
         )
 
+    def join(self, channels: Sequence[str]) -> PregelInvoke:
+        joiner = RunnablePassthrough.assign(
+            **{chan: PregelRead(chan) for chan in channels}
+        )
+        if isinstance(self.bound, RunnablePassthrough):
+            return PregelInvoke(channels=self.channels, bound=joiner)
+        else:
+            return PregelInvoke(channels=self.channels, bound=self.bound | joiner)
+
     def __or__(
         self,
         other: Runnable[Any, Other]