My bad, it's late in the evening here and I typed something that works when spoken with emphasis and timing (at least in my head).
I added quotes, it should say that Pakistan's weapons program is one that is outside the Nuclear Non-Proliferation Treaty as Pakistan is not a party to it.
We all know Israel isn’t party to it either.
Nor India, nor South Sudan. North Korea was, but didn't comply and then went backsies.
Of the four never did non signatories, South Sudan is not like the others (wrt one metric at least).