async+await 異步圖片爬蟲，最后幾張圖片超時錯誤？

最近想給自己的壁紙爬蟲用上協(xié)程提高速率，但是爬蟲速度越到后面越慢，且總是無法下載最后幾張圖片。如果用手機(jī)熱點的網(wǎng)絡(luò)下載（速度快得多）則可以成功下載所有圖片，不會出現(xiàn)上述問題。
會報如下的錯誤：

import os
import aiohttp
import asyncio

#圖片的url數(shù)組
pic_list=["http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_01origin_01_2017341744BB4.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_02origin_03_2017341744FC9.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_03origin_05_2017341744751.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_04origin_07_2017341744DD9.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_05origin_09_2017341744561.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_06origin_11_2017341744BE9.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_07origin_13_20173417443A2.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_5/gamersky_08origin_15_2017341744ABD.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_6/gamersky_02origin_03_2017341746E13.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_6/gamersky_03origin_05_201734174635D.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_6/gamersky_05origin_09_2017341746DF9.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_6/gamersky_06origin_11_20173417465EA.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_01origin_01_2017341747B6B.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_02origin_03_20173417474FD.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_03origin_05_20173417479AF.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_04origin_07_2017341747F66.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_05origin_09_20173417476EE.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_06origin_11_2017341747D76.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_07origin_13_20173417474FE.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_7/gamersky_08origin_15_2017341747B86.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_01origin_01_20173417485A9.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_02origin_03_2017341748B5D.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_03origin_05_20173417482D8.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_04origin_07_201734174812C.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_06origin_11_2017341748D6B.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_07origin_13_2017341748527.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_8/gamersky_08origin_15_2017341748C4C.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_01origin_01_2017341750ACF.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_02origin_03_2017341750ED1.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_04origin_07_2017341750B59.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_05origin_09_201734175013F.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_06origin_11_20173417507C7.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_9/gamersky_07origin_13_2017341750E4F.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_01origin_01_2017341753936.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_02origin_03_2017341753144.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_03origin_05_201734175369F.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_04origin_07_2017341753EFD.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_05origin_09_2017341753412.jpg", "http://img1.gamersky.com/image2017/03/20170304_zl_91_10/gamersky_06origin_11_201734175329A.jpg"]

#將單個圖片下載到本地
async def get_html(url):
    headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36'}
    async with aiohttp.ClientSession() as session:
        async with session.get(url, headers=headers) as r:
            path = os.path.join('wallpapers', url.split('/')[-1])
            fp = open(path, 'wb')
            fp.write(await r.read())
            fp.close()


def get_many(urls):

    loop = asyncio.get_event_loop()
    tasks = [get_html(url) for url in urls]

    loop.run_until_complete(asyncio.wait(tasks))
    loop.close()
    
    
get_many(pic_list)

希望能給出原因和優(yōu)化建議，謝謝