cmd进入Python安装路径scripts文件夹
>pip install requests
报错：
Collecting requests
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:777)'),)': /simple/requests/
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:777)'),)': /simple/requests/
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:777)'),)': /simple/requests/
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:777)'),)': /simple/requests/
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:777)'),)': /simple/requests/
Could not fetch URL https://pypi.python.org/simple/requests/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/requests/ (Caused by SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:777)'),)) - skipping
Could not find a version that satisfies the requirement requests (from versions: )
原因：查找网上的解释是网速太慢，或被墙了。
解决办法：使用国内镜像加速。
>pip install requests -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com
问题解决。