报错TypeError: object NoneType can't be used in 'await' expression？

Question

asyncio异步编程，给字典赋值，总是提示NoneType。

完整代码如下

import asyncio
import time
hs={}
def asy():
    #asynchronous
    start=time.perf_counter()
    def fn(i):
        hs[i]=i**9
    async def fastdofn(i):
        await fn(i)
    tasks=[asyncio.ensure_future(fastdofn(i)) for i in range(10)]
    loop = asyncio.get_event_loop()
    loop.run_until_complete(asyncio.wait(tasks))
    print(hs)
    print('runtime : {}'.format(time.perf_counter()-start))
asy()

运行结果：

{0: 0, 1: 1, 2: 512, 3: 19683, 4: 262144, 5: 1953125, 6: 10077696, 7: 40353607, 8: 134217728, 9: 387420489}
runtime : 0.049445499999999976
Task exception was never retrieved
future: <Task finished coro=<asy.<locals>.fastdofn() done, defined at C:\Users\QQ\Desktop\ls\py\异步.py:9> exception=TypeError("object NoneType can't be used in 'await' expression")>
Traceback (most recent call last):
  File "C:\Users\QQ\Desktop\ls\py\异步.py", line 10, in fastdofn
    await fn(i)
TypeError: object NoneType can't be used in 'await' expression

报错了10次

很奇怪的是，hs正常打印，而且达到了预期要求。为什么还会循环报错？

报错的问题解决了，但更懵了

import asyncio
import time
hs={}
def asy():
    #asynchronous
    start=time.process_time()
    def fn(i):
        hs[i]=i**9
    async def fastdofn(i):
        fn(i)
    tasks=[asyncio.ensure_future(fastdofn(i)) for i in range(100000)]
    loop = asyncio.get_event_loop()
    loop.run_until_complete(asyncio.wait(tasks))
    print(hs[9])
    ti=time.process_time()-start#time interval
    print('asy runtime : {}'.format(ti))
    return ti
def syn():
    #synchronization
    start=time.process_time()
    def fn(i):
        hs[i]=i**9
    for i in range(100000):
        fn(i)
    print(hs[9])
    ti=time.process_time()-start
    print('syn runtime : {}'.format(ti))
    return ti

def main():
    l1=[]
    l2=[]
    for i in range(1,11):
        print('{}th time'.format(i))
        asy()
        syn()
        print('\n')
    #print('asy is {} times faster than syn'.format(sum(l2)/sum(l1)))
main()

异步不应该比同步快么，怎么还慢了这么多？

Answer 1

await fn(i)改为fn(i)，await用于获取异步函数的回调，fn不是异步函数，所以这里会报一个错。