anchor.diff:  
       moveFile copyToDestination compareFiles deleteSource
   
  -let composeGetPictures sourceDir =
  +let composeGetPictures =
       let timeProvider () = DateTimeOffset.UtcNow
  -    let fileProvider = allFilesInPath sourceDir
   
  -    getOldPictures timeTaken timeProvider fileProvider
  +    getOldPictures timeTaken timeProvider
   
   [<EntryPoint>]
   let main argv =
  
positive.code:         ignore()
  
      let moves =
          getPictures
          |> getMoveRequests sourceDir
          |> Seq.map moveWithFs
          |> List.ofSeq
  
  
negative.code:     let destinationDir = arguments.GetResult <@ DestinationDir @>
  
  
      let getPictures = composeGetPictures
      let moveWithFs = composeMoveWithFs
  
      let printResult (moveResult:MoveResult) =
  