f-string fixer?

[xmo-odoo]

Python 3.6 adds f-string which are tremendously convenient, but can be an issue in two cases:

• making the codebase compatible with 3.5 after initial development
• making the codebase compatible with translations

Fixers able to convert back and forth between f-strings, str.format and str% would be nice.

[jmadler]

I'd definitely accept such a patch ;)

[jmadler]

This is related to #343

[thiborose]

Has anyone found a solution for this issue?