Python初学者请教：以下这段代码为什么会出错呢？

‘’
import logging;logging.basicConfig(level=logging.INFO)

import async, os, json, time
from datetime import datetime

from aiohttp import web

def index(request):
return web.Response(body=b’<h1>Awesome</h1>’)

@async.coroutine
def init(loop):
app = web.Application(loop=loop)
app.router.add_route(‘GET’, ‘/’, index)
srv = yield from loop.create_server(app.make_handler(),‘127.0.0.1’,9000)
logging.info(‘server started at http://127.0.0.1:9000…’)
return srv

loop = async.get_event_loop()
loop.run_until_complete(init(loop))
loop.run_forever()
"
运行上面的代码为什么会出现下面的错误？
srv=yield from loop.create_server(app.make_handler(),‘127.0.0.1’,9000)
^
SyntaxError: invalid syntax
Python初学者请教：以下这段代码为什么会出错呢？