报错：
NotImplementedError: Cannot execute CSS selectors because the soupsieve package is not installed.
是这个函数
def fetch_city_weather_url_list(url):
city_url_list = []
resp = requests.get(url)
resp.encoding = 'utf-8'
bs = BeautifulSoup(resp.text,'lxml')
# a_s = bs.find('a')
a_s = bs.select('div.conMidtab a')
因为是自学，有些知识不系统，在网上搜索很久没找到答案，后来回朋友才知道
