使用pip安装python包的时候，经常会出现以下类似的错误
(test) dongchang-5:test baoshan$ pip3 install requests Collecting requests Could not fetch URL https://pypi.python.org/simple/requests/: There was a problem confirming the ssl certificate: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:645) - skipping Could not find a version that satisfies the requirement requests (from versions: ) No matching distribution found for requests (test)
