docs/how_to/summarize_map_reduce/

[giscus[bot]]

docs/how_to/summarize_map_reduce/

LLMs can summarize and otherwise distill desired information from text, including large volumes of text. In many cases, especially when the amount of text is large compared to the size of the model's context window, it can be helpful (or necessary) to break up the summarization task into smaller components.

https://python.langchain.com/docs/how_to/summarize_map_reduce/

[ND56]

When I follow the pattern of using an edge to send chunks in parallel to a node (by causing the edge to return a list of send objects), I get the following type error complaining about that return type:

Type "list[Send]" is not assignable to type "Hashable | list[Hashable]"

Any thoughts on why that might be?

I'm using langgraph = "^0.4.0".

These are some code snippets:

# this is an example of how I register the "mapper" edge
graph.add_conditional_edges(
    "split_data_source", send_chunks_to_summarizer, ["generate_summary"]
)

# this is the mapper edge
def send_chunks_to_summarizer(state: GraphState):
    data_source_chunks = state["data_chunks"]

    return [
        Send(
            "generate_summary", {
                "data_chunk": data_chunk,
            }
        ) for data_chunk in data_source_chunks
    ]

Full Type Error:

Argument of type "(state: GraphState) -> list[Send]" cannot be assigned to parameter "path" of type "((...) -> (Hashable | list[Hashable])) | ((...) -> Awaitable[Hashable | list[Hashable]]) | Runnable[Any, Hashable | list[Hashable]]" in function "add_conditional_edges"
  Type "(state: GraphState) -> list[Send]" is not assignable to type "((...) -> (Hashable | list[Hashable])) | ((...) -> Awaitable[Hashable | list[Hashable]]) | Runnable[Any, Hashable | list[Hashable]]"
    Type "(state: GraphState) -> list[Send]" is not assignable to type "(...) -> (Hashable | list[Hashable])"
      Function return type "list[Send]" is incompatible with type "Hashable | list[Hashable]"
        Type "list[Send]" is not assignable to type "Hashable | list[Hashable]"
          "list[Send]" is incompatible with protocol "Hashable"
          "list[Send]" is not assignable to "list[Hashable]"
    Type "(state: GraphState) -> list[Send]" is not assignable to type "(...) -> Awaitable[Hashable | list[Hashable]]"
Function return type "list[Send]" is incompatible with type "Hashable | list[Hashable]"
        Type "list[Send]" is not assignable to type "Hashable | list[Hashable]"
          "list[Send]" is incompatible with protocol "Hashable"
          "list[Send]" is not assignable to "list[Hashable]"
    Type "(state: GraphState) -> list[Send]" is not assignable to type "(...) -> Awaitable[Hashable | list[Hashable]]"
      Function return type "list[Send]" is incompatible with type "Awaitable[Hashable | list[Hashable]]"
  ...PylancereportArgumentType