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What is an async generator, and how does it differ from a regular generator? How do you consume an async generator using 'async for'? What is an async context manager, and which two dunder methods does it require? How does an async generator interact with try/finally for guaranteed cleanup, similar to regular generators? How do you build an async generator pipeline, chaining one async generator's output into another, like a synchronous generator pipeline? How do async comprehensions work, combining 'async for' directly inside a list/set/dict comprehension? How would you implement a custom async iterator class from scratch, without using an async generator function? How do you handle backpressure when an async generator produces items faster than the consumer can process them? How would you implement timeout handling for an async generator's individual yields, so a stalled source doesn't hang the consumer forever? How do async generators interact with asyncio.Queue to implement a producer-consumer pattern across separate tasks?
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How do you write an async context manager more concisely using @contextlib.asynccontextmanager?

Intermediate

Answer

asynccontextmanager decorates a single async generator function: code before the 'yield' runs as __aenter__, the yielded value becomes the 'as' target, and code after 'yield' (typically in a try/finally) runs as __aexit__ — avoiding the need to write a full class with both dunder methods.
from contextlib import asynccontextmanager

@asynccontextmanager
async def async_connection():
    conn = await connect()
    try:
        yield conn
    finally:
        await conn.close()

async def main():
    async with async_connection() as conn:
        await conn.query("SELECT 1")
Real-world example Writing a lightweight, function-based async resource manager without the boilerplate of a full __aenter__/__aexit__ class.

Common follow-ups: How does this asynccontextmanager decorator compare to the synchronous @contextlib.contextmanager?

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All 15 Async Generators & Async Context Managers questions