[Solved] What is wrong with this code snippet?parallel = RunnableParallel(task1, task2) results = parallel.invoke() | LangChain

LangChain - Chains and LCEL

What is wrong with this code snippet?

parallel = RunnableParallel(task1, task2)
results = parallel.invoke()

ARunnableParallel requires tasks inside a dictionary, not separate arguments

Binvoke() method does not exist on RunnableParallel

CYou must call run() instead of invoke()

DRunnableParallel cannot run more than one task

Step-by-Step Solution

Solution:

Step 1: Check RunnableParallel constructor usage
RunnableParallel expects a dictionary of tasks, not separate positional arguments.
Step 2: Identify the error in code
Passing task1, task2 as separate positional arguments causes a TypeError.
Final Answer:
RunnableParallel requires tasks inside a dictionary, not separate arguments -> Option A
Quick Check:
Tasks must be in a dictionary [OK]

Quick Trick: Always use a dictionary or named kwargs for RunnableParallel tasks [OK]

Common Mistakes:

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