A.venv/bin/python B.sourcevenv/bin/activate C.workonvenv D.pipenvshell
A.pipinstallDjango>=1.8 B.pipinstall-rrequirements.txt C.pip-egit+http://git.example.com/MyProject#egg=MyProject D.pipinstall./SomePackage-1.0.4.tar.gz
A.__with__ B.__enter__ C.__open__ D.__exit__