Same translatable string used in different contexts

While going through the translation in software-center, I found one string, that is usually "hard" to translate correctly without a little bit of context, that is being used in three different contexts, with at least two different meanings.

The translatable string is: "Free".

The string already has translator comments before, but unfortunately this is not enough. The same string looks like is used in 4 different files, and has 2 different meanings, at least looking at the translator comments before.

The problem is that Launchpad is showing us only 1 translatable string, instead of at least 2.

The translator comments used are:
TRANSLATORS: Free here means Gratis
TRANSLATORS: Free here means Libre
TRANSLATORS: Free here means Gratis

The strings are located in the following files:
 ../softwarecenter/db/application.py:607
../softwarecenter/db/application.py:622
../softwarecenter/ui/gtk3/views/appdetailsview.py:402
../softwarecenter/ui/gtk3/views/appdetailsview.py:691

It would be best to use msgctxt: the problem being if Python 2.7 supports it out-of-the-box.