what should gen do?

[Martin R]

I am unsure about the meaning of the method "gen", specifically, in the context of lazy Dirichlet series, which are introduced in

https://trac.sagemath.org/ticket/32324

Should gen(n) return n^-s, or nth_prime(n)^-s, or nth_prime(n+1)^-s, or should it rather not exist at all?

Martin