def Prod.value
import bend-collections-laws-math@1.0.0.0/spec/math/natural.bend as Naturalimport Base
import bend-collections-laws-math@1.0.0.0/src/math/natural.bend as M
177def Prod.value(+xs: List<&2, Nat>) -> Type:
178 {M.prod(xs) == lprod(xs) : Nat}