(I'm the guy who started Sage.) Sage has the Jacobi symbol as of 7 years ago (see https://trac.sagemath.org/ticket/11138 https://trac.sagemath.org/ticket/1113

(I'm the guy who started Sage.) Sage has the Jacobi symbol as of 7 years ago (see https://trac.sagemath.org/ticket/11138 https://trac.sagemath.org/ticket/11138 and https://github.com/sagemath/sage/blob/07d6c37d18811e2b377a9689790a7c5e24da16ba/src/sage/arith/misc.py#L3426 https://github.com/sagemath/sage/blob/07d6c37d18811e2b377a96...). Sage is pretty good at primality testing, because PARI is. I'm really glad that the author of this library is enjoying writing Algebraic number theory that is readable and in Python3. Go for it, and have fun!