I was watching a video of a PyCon 2018 conference talk by Hillel Wayne titled Beyond Unit Tests: Taking Your Testing to the Next Level
He was starting a “Design by contract” part of the speech (about min 18), and said:
It turns out this is actually one of the most powerful verification techniques we know about
We’ve seen it work empirically at scale in all sorts of places but these places have mostly been avionics critical systems defense academia so nobody’s heard of this thing which honestly I find completely crazy.
I mean here’s a question how many of you’ve heard of Ada?
how many of you actually looked into what Ada can do?
ok I’ve actually done some experimentation: you can do incredible things with Ada, but because it’s Ada nobody cares.
Couldn’t summarize the situation any better 
And then later (around min 28), about Formal Method :
This is the study of how we can prove software is correct at a level not seen in any kind of modern-day production language
Nothing really approach this level that we can do with formal methods not
actually yet Ada can do it never mind!
Kudos to Hillel Wayne, someone who talks about Ada after actually trying it.
Useless to say I clicked the thumbs up!
