pip安装失败：attributeerror: ‘module’ object has no attribute ‘ssl_st_init’

问题现象：
pip install执行失败时，报错误’module’ object has no attribute ‘SSL_ST_INIT’：
具体错误信息如下：
Traceback (most recent call last):
File “/usr/local/bin/pip”, line 9, in
load_entry_point(‘pip==10.0.1’, ‘console_scripts’, ‘pip’)()
File “/usr/lib/python2.7/dist-packages/pkg_resources/init.py”, line 542, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)

File “/usr/lib/python2.7/dist-packages/pkg_resources/init.py”, line 2569, in load_entry_point
return ep.load()
File “/usr/lib/python2.7/dist-packages/pkg_resources/init.py”, line 2229, in load
return self.resolve()
File “/usr/lib/python2.7/dist-packages/pkg_resources/init.py”, line 2235, in resolve
module = import(self.module_name, fromlist=[‘name‘], level=0)
File “/usr/local/lib/python2.7/dist-packages/pip-10.0.1-py2.7.egg/pip/_internal/init.py”, line 42, in
from pip._internal import cmdoptions
File “/usr/local/lib/python2.7/dist-packages/pip-10.0.1-py2.7.egg/pip/_internal/cmdoptions.py”, line 16, in
from pip._internal.index import (
File “/usr/local/lib/python2.7/dist-packages/pip-10.0.1-py2.7.egg/pip/_internal/index.py”, line 15, in
from pip._vendor import html5lib, requests, six
File “/usr/local/lib/python2.7/dist-packages/pip-10.0.1-py2.7.egg/pip/_vendor/requests/init.py”, line 86, in
from pip._vendor.urllib3.contrib import pyopenssl
File “/usr/local/lib/python2.7/dist-packages/pip-10.0.1-py2.7.egg/pip/_vendor/urllib3/contrib/pyopenssl.py”, line 46, in
import OpenSSL.SSL
File “/usr/lib/python2.7/dist-packages/OpenSSL/init.py”, line 8, in
from OpenSSL import rand, crypto, SSL
File “/usr/lib/python2.7/dist-packages/OpenSSL/SSL.py”, line 118, in
SSL_ST_INIT = _lib.SSL_ST_INIT
AttributeError: ‘module’ object has no attribute ‘SSL_ST_INIT’

问题原因：
OpenSSL版本太低

解决办法：
https://stackoverflow.com/questions/51019860/error-with-pip-after-upgrading-module-object-has-no-attribute-ssl-st-init
python -m easy_install –upgrade pyOpenSSL