error after upgrade pandas-datareader

I have a script that run without error before. However, I updates pandas-datareader and then my script come with this error

/home/vinus/.local/lib/python2.7/site-packages/urllib3/util/ InsecurePlatformWarning: A true SSLContext object is not available. This p
revents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to s
olve this. For more information, see

what is this problem? I use pip2.7 install --user pandas-datareader --upgrade

There's a link in the warning that leads to instructions about what to do. Follow the link and do the things it suggests.