anchor.diff:  
       [<Test>]
       member __.``1. Parallel : empty input`` () =
  -        run (Cloud.Parallel Array.empty<Cloud<int>> ) |> Choice.shouldEqual [||]
  +        Array.empty<Cloud<int>> |> Cloud.Parallel |> run |> Choice.shouldEqual [||]
   
       [<Test>]
       member __.``1. Parallel : simple inputs`` () =
  
positive.code:     [<Test>]
      member __.``2. Choice : empty input`` () =
          Cloud.Choice List.empty<Cloud<int option>> |> run |> Choice.shouldEqual None
  
      [<Test>]
      member __.``2. Choice : all inputs 'None'`` () =
  
negative.code:             let! results = Seq.init nParallel f |> Cloud.Parallel
              return Array.sum results
          } |> run |> Choice.shouldEqual (Seq.init nParallel (fun i -> i + 1) |> Seq.sum)
  
      [<Test>]
      member __.``1. Parallel : random inputs`` () =
          let checker (ints:int[]) =
              if ints = null then () else
              let maxSize = 5 * nParallel
              let ints = if ints.Length <= maxSize then ints else ints.[..maxSize]
              cloud {
                  let f i = cloud { return ints.[i] }
                  return! Seq.init ints.Length f |> Cloud.Parallel
              } |> run |> Choice.shouldEqual ints
  
          Check.QuickThrowOnFail(checker, maxRuns = self.FsCheckMaxTests)
  
      [<Test>]
      member __.``1. Parallel : use binding`` () =
  