List checkpoints from the database.
This method retrieves a list of checkpoint tuples from the Postgres database based on the provided config. For ShallowPostgresSaver, this method returns a list with ONLY the most recent checkpoint.
list(
self,
config: RunnableConfig | None,
*,
filter: dict[str, Any] | None = None,
before: RunnableConfig | None = None,
limit: int | None = None
) -> Iterator[CheckpointTuple]