 }
 
 extension PrimitiveSequence where Trait == SingleTrait {
-
   static func fromSinglesToSingleOfArray(_ singles: [Single<Element>]) -> Single<[Element]> {
     Observable
       .merge(singles.map { $0.asObservable() })

}

extension PrimitiveSequence where Element == Never, Trait == CompletableTrait {

  func andThen(using body: () -> Completable) -> Completable { self.andThen(body()) }

  func wait(

    onError: ((Swift.Error) -> Void)? = nil
  ) throws {
    var trigger = false
    var err: Swift.Error?

    let condition = NSCondition()

