使用pip和easy_install安装那个lxml、pyspider这些库或者框架一直提示以下错误：
Collecting pyspider
Could not fetch URL https://pypi.python.org/simple/pyspider/: There was a prob
lem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate
verify failed (_ssl.c:661) - skipping
Could not find a version that satisfies the requirement pyspider (from version
s: )
No matching distribution found for pyspider
Searching for pyspider
Reading https://pypi.python.org/simple/pyspider/
Download error on https://pypi.python.org/simple/pyspider/: [SSL: CERTIFICATE_VE
RIFY_FAILED] certificate verify failed (_ssl.c:661) -- Some packages may not be
found!
Couldn't find index page for 'pyspider' (maybe misspelled?)
Scanning index of all packages (this may take a while)
Reading https://pypi.python.org/simple/
Download error on https://pypi.python.org/simple/: [SSL: CERTIFICATE_VERIFY_FAIL
ED] certificate verify failed (_ssl.c:661) -- Some packages may not be found!
No local packages or working download links found for pyspider
error: Could not find suitable distribution for Requirement.parse('pyspider')
错误原因：SSL：CERTIFICATE_VERIFY_FAILED]证书验证失败（_ssl.c：661）
解决办法：
# 1.pip install --index-url=http://pypi.python.org/simple/ --trusted-host pypi.python.org pythonPackageName
# 2.pip --trusted-host pypi.python.org install pythonPackageName
以上两种命令都行，其中 "pythonPackageName" 是你要安装的库名称（比如：requests、lxml等）