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這是例如取消任務：如何取消任務執行，即使它忽略了CancelledError？
import asyncio
async def some_func():
await asyncio.sleep(2)
print('Haha! Task keeps running!')
await asyncio.sleep(2)
async def cancel(task):
await asyncio.sleep(1)
task.cancel()
async def main():
func_task = asyncio.ensure_future(some_func())
cancel_task = asyncio.ensure_future(cancel(func_task))
try:
await func_task
except asyncio.CancelledError:
print('Task cancelled as expected')
if __name__ == "__main__":
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
# Task cancelled as expected
# [Finished in 1.2s]
它工作正常，任務被取消。如果抓到裏面some_func任務CancelledError不會被取消：
async def some_func():
try:
await asyncio.sleep(2)
except:
pass
print('Haha! Task keeps running!')
await asyncio.sleep(2)
# Haha! Task keeps running!
# [Finished in 3.2s]
它可以很容易忘記我不應該抑制異常裏面異步代碼的任何地方（或some_func可以是第三方的代碼，例如），但任務應取消。無論如何，我可以做到這一點？或者被忽略CancelledError意味着任務完全不能被取消？