Revert "Make the FANTOIR code more pythonic"

Summary:
This reverts commit 22090aeb3a7ed4e752d8429bbb66f6c9a392a417.

Commit was wrongly marked as authored by @dereckson by Arcanist,
but it has been authored by @xcombelle.

Reviewers: dereckson

Reviewed By: dereckson

Subscribers: xcombelle

Differential Revision: https://devcentral.nasqueron.org/D1232