当我运行下面的代码时，出现此错误：
TypeError: Use async with instead
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x0000023D639B0DA0>
该代码直接从以下位置复制：https://www.artificialworlds.net/blog/2017/06/12/making-100-million-requests-with-python-aiohttp/。注意，我尝试添加session.close（）来关闭会话，但仍然收到该错误。
from aiohttp import ClientSession
import asyncio
import sys
limit = 1000
async def fetch(url, session):
async with session.get(url) as response:
return await response.read()
async def bound_fetch(sem, url, session):
# Getter function with semaphore.
async with sem:
await fetch(url, session)
async def run(session, r):
url = "http://localhost:8080/{}"
tasks = []
# create instance of Semaphore
sem = asyncio.Semaphore(limit)
for i in range(r):
# pass Semaphore and session to every GET request
task = asyncio.ensure_future(bound_fetch(sem, url.format(i), session))
tasks.append(task)
responses = asyncio.gather(*tasks)
await responses
loop = asyncio.get_event_loop()
with ClientSession() as session:
loop.run_until_complete(asyncio.ensure_future(run(session, int(sys.argv[1]))))