on pypi.python.org I see, that latest version of requests
is 2.2.1
Your listing shows, you have installed version 2.3.0, so it is likely, you are using development version which is not yet really completed.
Uninstal it:
$ pip uninstall requests
And install production quality one:
$ pip install requests
In case, it would still mess up with version 2.3.0, install explicitly the 2.2.1
$ pip install requests==2.2.1