[Solved] Identify the error in this lifespan context manager code?async def lifespan(app: FastAPI): print('Start') yield 123 print('Stop') | FastAPI

FastAPI - Middleware and Hooks

Identify the error in this lifespan context manager code?

async def lifespan(app: FastAPI):
    print('Start')
    yield 123
    print('Stop')

AMissing await before print causes error

BApp parameter must be optional

CYielding a value other than null is not allowed in lifespan

DPrint statements cannot be inside lifespan

Step-by-Step Solution

Solution:

Step 1: Understand yield value in lifespan
Lifespan expects yield with no value (null) to separate startup/shutdown.
Step 2: Effect of yielding 123
Yielding a non-null value is not allowed in FastAPI lifespan.
Final Answer:
Yielding a value other than null is not allowed in lifespan -> Option C
Quick Check:
Yield only null in lifespan [OK]

Quick Trick: Lifespan requires `yield` without a value [OK]

Common Mistakes:

MISTAKES

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Identify the error in this lifespan context manager code?