INVALID_GRAPH_NODE_RETURN_VALUE

class State(TypedDict):
    some_key: str

def bad_node(state: State):
    # Should return a dict with a value for "some_key", not a list
    return ["whoops"]

builder = StateGraph(State)
builder.add_node(bad_node)
...

graph = builder.compile()

graph.invoke({ "some_key": "someval" });

InvalidUpdateError: Expected dict, got ['whoops']
For troubleshooting, visit: https://docs.langchain.com/oss/python/langgraph/errors/INVALID_GRAPH_NODE_RETURN_VALUE