突然使用python直接使用pip install xx时，出现报错：
Could not fetch URL https://pypi.org/simple/pymysql/: There was a problem confirming the ssl certificate: HTTPSConnectio
nPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pymysql/ (Caused by SSLError(SSLError(1, '[SSL:
CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)) - skipping
报错内容如下：
PS C:\Users\yinha> pip install pymysql
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)': /simple/pymysql/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)': /simple/pymysql/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)': /simple/pymysql/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)': /simple/pymysql/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)': /simple/pymysql/
Could not fetch URL https://pypi.org/simple/pymysql/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pymysql/ (Caused by SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:852)'),)) - skipping
ERROR: Could not find a version that satisfies the requirement pymysql (from versions: none)
ERROR: No matching distribution found for pymysql
一开始以为是ide环境出了问题，后来在终端，在虚拟环境测试都会报错。
1. 重装python
无效
2.重装pip
无效
python -m pip uninstall pip
C:\Python36\Scripts>easy_install.exe -i http://mirrors.aliyun.com/pypi/simple/ pip
3.添加--trusted-host
有效
但是每次安装增加此参数，比较麻烦
pip install pymysql -i http://pypi.tuna.tsinghua.edu.cn/simple/ --trusted-host pypi.tuna.tsinghua.edu.cn
4.创建pip配置pip.ini。
有效
（1）在系统目录C:\Users\用户\AppData\Roaming新建pip文件夹；
（2）在pip文件夹下新建pip.ini文件，并写入如下配置：
[global]
index-url = http://mirrors.aliyun.com/pypi/simple/
[install]
trusted-host = mirrors.aliyun.com
5.关闭Fiddler
看到这里真的是崩溃，开启它之后运行python会自动改变端口，造成ssl错误。
不多解释了，关掉就好，说多了都是泪。
顺便说一下：开启
Fiddler
后，对requests模块也会产生ssl认证的报错。
之前没发现这个原因时，就靠如下方法对付：
# 忽略警告
requests.packages.urllib3.disable_warnings()
#取消认证
requests.get(url=url,cookies=cookies,verify=False)
