RuntimeError：无法从正在运行的事件循环中调用 asyncio.run()

Question

I am running the simplest of examples on asyncio:

import asyncio

async def main():
    print("A")
    await asyncio.sleep.sleep(1)
    print("B")

asyncio.run(main())

and I get a runtime error: RuntimeError: asyncio.run() cannot be called from a running event loop

I am using Spyder (Python 3.9) on an M1 Mac (...if that matters).

the outcome expected is:

A

B

Process finished with exit code 0

Answer 1

But for the ".sleep.sleep" this code is fine - "event loop already running" is certainly not an issue for a standalone script with this code.

Maybe you are running it in as a notebook cell, with some asyncio state already set-up?

In a bash terminal, I pasted your code as is, and just replaced the incorrect function name:

[gwidion@fedora tmp01]$ cat >bla42.py
import asyncio

async def main():
    print("A")
    await asyncio.sleep.sleep(1)
    print("B")

asyncio.run(main())

[gwidion@fedora tmp01]$ python bla42.py
A
Traceback (most recent call last):
[...]
  File "/home/gwidion/tmp01/bla42.py", line 5, in main
    await asyncio.sleep.sleep(1)
AttributeError: 'function' object has no attribute 'sleep'
[gwidion@fedora tmp01]$ python -c 'open("bla43.py", "w").write(open("bla42.py").read().replace(".sleep.sleep", ".sleep"))'
[gwidion@fedora tmp01]$ python bla43.py
A
B
[gwidion@fedora tmp01]$