From d3bb2b9aa0424e603a7c2b2e06fb637beeb85393 Mon Sep 17 00:00:00 2001
From: Nuno Campos <nuno@langchain.dev>
Date: Thu, 20 Mar 2025 08:18:17 -0700
Subject: [PATCH] Lint

---
 libs/langgraph/langgraph/pregel/__init__.py | 8 ++++----
 libs/langgraph/langgraph/pregel/algo.py     | 6 +++---
 libs/langgraph/langgraph/pregel/loop.py     | 6 +++---
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/libs/langgraph/langgraph/pregel/__init__.py b/libs/langgraph/langgraph/pregel/__init__.py
index 79470680b..ac1f2781d 100644
--- a/libs/langgraph/langgraph/pregel/__init__.py
+++ b/libs/langgraph/langgraph/pregel/__init__.py
@@ -504,7 +504,7 @@ class Pregel(PregelProtocol):
 
     name: str = "LangGraph"
 
-    trigger_to_nodes: dict[str, set[str]] = None
+    trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None
 
     def __init__(
         self,
@@ -2749,10 +2749,10 @@ class Pregel(PregelProtocol):
             return chunks
 
 
-def _trigger_to_nodes(nodes: dict[str, PregelNode]) -> Mapping[str, list[str]]:
+def _trigger_to_nodes(nodes: dict[str, PregelNode]) -> Mapping[str, Sequence[str]]:
     """Index from a trigger to nodes that depend on it."""
     trigger_to_nodes: defaultdict[str, list[str]] = defaultdict(list)
     for name, node in nodes.items():
         for trigger in node.triggers:
-            trigger_to_nodes.setdefault(trigger, []).append(name)
-    return cast(Mapping[str, list[str]], trigger_to_nodes)
+            trigger_to_nodes[trigger].append(name)
+    return dict(trigger_to_nodes)
diff --git a/libs/langgraph/langgraph/pregel/algo.py b/libs/langgraph/langgraph/pregel/algo.py
index 4546ab300..01d724c9f 100644
--- a/libs/langgraph/langgraph/pregel/algo.py
+++ b/libs/langgraph/langgraph/pregel/algo.py
@@ -347,7 +347,7 @@ def prepare_next_tasks(
     store: Literal[None] = None,
     checkpointer: Literal[None] = None,
     manager: Literal[None] = None,
-    trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+    trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     updated_channels: Optional[set[str]] = None,
 ) -> dict[str, PregelTask]: ...
 
@@ -366,7 +366,7 @@ def prepare_next_tasks(
     store: Optional[BaseStore],
     checkpointer: Optional[BaseCheckpointSaver],
     manager: Union[None, ParentRunManager, AsyncParentRunManager],
-    trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+    trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     updated_channels: Optional[set[str]] = None,
 ) -> dict[str, PregelExecutableTask]: ...
 
@@ -384,7 +384,7 @@ def prepare_next_tasks(
     store: Optional[BaseStore] = None,
     checkpointer: Optional[BaseCheckpointSaver] = None,
     manager: Union[None, ParentRunManager, AsyncParentRunManager] = None,
-    trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+    trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     updated_channels: Optional[set[str]] = None,
 ) -> Union[dict[str, PregelTask], dict[str, PregelExecutableTask]]:
     """Prepare the set of tasks that will make up the next Pregel step.
diff --git a/libs/langgraph/langgraph/pregel/loop.py b/libs/langgraph/langgraph/pregel/loop.py
index a55941a30..f21d61442 100644
--- a/libs/langgraph/langgraph/pregel/loop.py
+++ b/libs/langgraph/langgraph/pregel/loop.py
@@ -210,7 +210,7 @@ class PregelLoop(LoopProtocol):
         manager: Union[None, AsyncParentRunManager, ParentRunManager] = None,
         input_model: Optional[Type[BaseModel]] = None,
         debug: bool = False,
-        trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+        trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     ) -> None:
         super().__init__(
             step=0,
@@ -893,7 +893,7 @@ class SyncPregelLoop(PregelLoop, ContextManager):
         stream_keys: Union[str, Sequence[str]] = EMPTY_SEQ,
         input_model: Optional[Type[BaseModel]] = None,
         debug: bool = False,
-        trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+        trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     ) -> None:
         super().__init__(
             input,
@@ -1036,7 +1036,7 @@ class AsyncPregelLoop(PregelLoop, AsyncContextManager):
         stream_keys: Union[str, Sequence[str]] = EMPTY_SEQ,
         input_model: Optional[Type[BaseModel]] = None,
         debug: bool = False,
-        trigger_to_nodes: Optional[Mapping[str, list[str]]] = None,
+        trigger_to_nodes: Optional[Mapping[str, Sequence[str]]] = None,
     ) -> None:
         super().__init__(
             input,