def step_acc
import bend-collections@1.0.0.0/src/containers/stack.bend as Stackimport Base
import bend-collections@1.0.0.0/src/containers/types/stack.bend as E
69def step_acc(~T: Data, op: E.Op<T>, st: Stack<T> & List<&2, E.Obs<T>>) -> Stack<T> & List<&2, E.Obs<T>>:
70 (q, acc) = st
71 record(~T, acc, step(~T, q, op))