def obs_list
import bend-collections@1.0.0.0/src/containers/dynamic_array.bend as DynamicArrayimport Base
import bend-collections@1.0.0.0/src/containers/types/dynamic_array.bend as E
249def obs_list(-T: Data, r: DynArray<&2, T> & List<&2, T>) -> DynArray<&2, T> & E.Obs<T>:
250 (d, xs) = r
251 (d, E.OList{xs})