def step_handle
import bend-collections@1.0.0.0/src/containers/doubly_linked_list.bend as DoublyLinkedListimport Base
import bend-collections@1.0.0.0/src/containers/types/doubly_linked_list.bend as E
207def step_handle(~T: Data, s: DList<T>, op: E.Op<T>, h: Maybe<&2, E.Handle>) -> DList<T> & E.Obs<T>:
208 match h:
209 case None{}:
210 dispatch(~T, s, op)
211 case Some{handle}:
212 checked(~T, op, validate(~T, s, handle))