I am on osx. And for my particular project I am stuck with python 2.7. (I think python 3 is fine at the moment.) Apparently pip has been acting up. If you do a pip install and getting something like this:

[code] Collecting alembic==0.9.5 (from -r requirements.txt (line 1)) Could not fetch URL https://pypi.python.org/simple/alembic/: There was a problem confirming the ssl certificate: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:590) - skipping Could not find a version that satisfies the requirement alembic==0.9.5 (from -r requirements.txt (line 1)) (from versions: ) No matching distribution found for alembic==0.9.5 (from -r requirements.txt (line 1)) [/code]

Check your pip version. pip –version. If you have 9.0.1, that’s the bad version. You will need to get to 9.0.2 or 9.0.3, or maybe version 10, but I will explain later.

If you do pip install –upgrade pip==9.0.3, that will fail with the same ssl error.

Don’t do curl https://bootstrap.pypa.io/get-pip.py | python at this point, because that will give you the pip version 10, which you may keep getting errors like this whenever you use pip.

[code] from pip._internal import main ImportError: No module named _internal [/code]

If you are making a system-wide change to your pip, then here is how. First remove pip, then install it back.

[code] sudo pip uninstall pip python -m ensurepip curl https://bootstrap.pypa.io/2.6/get-pip.py | python [/code]

The python -m ensurepip will give you pip 6.1.1, then the get-pip.py call will give you pip 9.0.3. Then you are all set.

If you are making a change to a virtual environment, depending on which python (-p) param you provide, mkvirtualenv always gives me pip 9.0.1 (bad) or pip 10 (bad).

If you end up having pip 10, try pip install pip==9.0.3. If that works then good for you, you can stop here. Otherwise, do the following.

We will need to install another version of python from homebrew.

[code] brew install python2 mkvirtualenv -p /usr/local/Cellar/python\@2/2.7.14_3/bin/python2.7 your_env_name pip –version pip install pip==9.0.3 [/code]

After the mkvirtualenv call, the pip version is 10. Then you can downgrade to 9.0.3.

That’s all if you have to stick with python 2.7. My other projects using python 3 seem ok.