def step_acc
import bend-collections@1.0.0.0/src/containers/internal/dlist_storage.bend as DlistStorageimport Base
import bend-collections@1.0.0.0/src/containers/types/internal_dlist.bend as E
511def step_acc(~T: Data, op: E.Op<T>, st: DList<T> & List<&2, E.Obs<T>>) -> DList<T> & List<&2, E.Obs<T>>:
512 (s, acc) = st
513 record(~T, acc, step(~T, s, op))