遇到500大坑了，请指导下怎么查找错误呢？ ERROR:aiohttp.server:Error handling request Traceback (most recent call last): File "C:\Users\Administrator\Python35-32\lib\site-packages\aiohttp\webserver. py", line 61, in handlerequest resp = yield from self.handler(request) File "C:\Users\Administrator\Python35-32\lib\site-packages\aiohttp\web.py", li ne 249, in handle resp = yield from handler(request) File "app.py", line 50, in logger return (yield from handler(request)) File "app.py", line 72, in response r = yield from handler(request) File "C:\Users\Administrator\Python35-32\lib\site-packages\aiohttp\web_urldisp atcher.py", line 113, in handler_wrapper result = yield from result File "C:\Users\Administrator\Python35-32\coroweb.py", line 139, in __call r = yield from self._func(**kw) File "C:\Users\Administrator\Python35-32\lib\asyncio\coroutines.py", line 209, in coro res = yield from res File "C:\Users\Administrator\Python35-32\handlers.py", line 19, in index users = yield from User.findAll() File "C:\Users\Administrator\Python35-32\orm.py", line 196, in findAll rs = yield from select(' '.join(sql), args) File "C:\Users\Administrator\Python35-32\orm.py", line 41, in select with pool.get() as conn: File "C:\Users\Administrator\Python35-32\lib\site-packages\aiomysql\utils.py", line 171, in enter assert self._conn AssertionError INFO:aiohttp.access:127.0.0.1 - - [22/Jan/2017:14:10:27 +0000] "GET / HTTP/1.1" 500 141 "-" "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36"

求高人帮忙，指导下如何查找问题。