Merge pull request #1771 from langchain-ai/nc/19sep/mypy-langgraph-partial

Enable mypy for langgraph lib

libs/checkpoint-postgres/langgraph/checkpoint/postgres/__init__.py

@@ -1,6 +1,6 @@
 import threading
 from contextlib import contextmanager
-from typing import Any, Iterator, List, Optional, Union
+from typing import Any, Iterator, Optional, Sequence, Union
 
 from langchain_core.runnables import RunnableConfig
 from psycopg import Connection, Cursor, Pipeline
@@ -332,7 +332,7 @@ class PostgresSaver(BasePostgresSaver):
     def put_writes(
         self,
         config: RunnableConfig,
-        writes: List[tuple[str, Any]],
+        writes: Sequence[tuple[str, Any]],
         task_id: str,
     ) -> None:
         """Store intermediate writes linked to a checkpoint.

libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py

@@ -1,6 +1,6 @@
 import asyncio
 from contextlib import asynccontextmanager
-from typing import Any, AsyncIterator, Iterator, List, Optional, Union
+from typing import Any, AsyncIterator, Iterator, Optional, Sequence, Union
 
 from langchain_core.runnables import RunnableConfig
 from psycopg import AsyncConnection, AsyncCursor, AsyncPipeline
@@ -291,7 +291,7 @@ class AsyncPostgresSaver(BasePostgresSaver):
     async def aput_writes(
         self,
         config: RunnableConfig,
-        writes: list[tuple[str, Any]],
+        writes: Sequence[tuple[str, Any]],
         task_id: str,
     ) -> None:
         """Store intermediate writes linked to a checkpoint asynchronously.
@@ -425,7 +425,7 @@ class AsyncPostgresSaver(BasePostgresSaver):
     def put_writes(
         self,
         config: RunnableConfig,
-        writes: List[tuple[str, Any]],
+        writes: Sequence[tuple[str, Any]],
         task_id: str,
     ) -> None:
         """Store intermediate writes linked to a checkpoint.

libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py

@@ -1,5 +1,5 @@
 import random
-from typing import Any, List, Optional, Tuple, cast
+from typing import Any, List, Optional, Sequence, Tuple, cast
 
 from langchain_core.runnables import RunnableConfig
 from psycopg.types.json import Jsonb
@@ -209,7 +209,7 @@ class BasePostgresSaver(BaseCheckpointSaver[str]):
         checkpoint_ns: str,
         checkpoint_id: str,
         task_id: str,
-        writes: list[tuple[str, Any]],
+        writes: Sequence[tuple[str, Any]],
     ) -> list[tuple[str, str, str, str, int, str, str, bytes]]:
         return [
             (