Watch the Jumping Whole Tones online guitar lesson by Reinier Voet from 50 Gypsy Jazz Licks You MUST Know
In this section I will show you how to use an augmented 5th in a prefab lick. It is a way to let the dominant 7th chord sound more exciting, a bit strange, maybe more jazzy. Mind you, it is not particularily modern. This augmented 5th was already used in classical music, for example by Claude Debussy. Django was a Debussy admirer and used it quite often as well.