From e566ed4b3fd04962fddd3ae95959a671645d652d Mon Sep 17 00:00:00 2001
From: Nuno Campos <nuno@langchain.dev>
Date: Tue, 11 Mar 2025 17:51:13 -0700
Subject: [PATCH] Fix py 3.9

- isclass and issubclass disagree on whether something like list[str] is a class
---
 libs/langgraph/langgraph/graph/state.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libs/langgraph/langgraph/graph/state.py b/libs/langgraph/langgraph/graph/state.py
index 45564334f..1b5ef0191 100644
--- a/libs/langgraph/langgraph/graph/state.py
+++ b/libs/langgraph/langgraph/graph/state.py
@@ -627,7 +627,9 @@ class StateGraph(Graph):
             builder=self,
             config_type=self.config_schema,
             input_model=self.input
-            if isclass(self.input) and issubclass(self.input, (BaseModel, BaseModelV1))
+            if len(self.channels) > 1
+            and isclass(self.input)
+            and issubclass(self.input, (BaseModel, BaseModelV1))
             else None,
             nodes={},
             channels={