def Deque.pop_front.refill
import bend-kit-collections@0.1.4.1/deque.bend as Dequeimport Base
94def Deque.pop_front.refill(
95 a, -A: Kind(a), bn: List<a, A> & Nat
96) -> Maybe<&1, A & Deque<a, A>>:
97 (b, n) = bn
98 Deque.pop_front.halves(a, A, Deque.split(a, A, Deque.half(n), b))