anchor.diff:          newDependenciesFile.Save()
           newDependenciesFile
   
  +type UpdateMode =
  +    | SelectiveUpdate of NormalizedPackageName
  +    | Install
  +    | UpdateAll
  +
  +    static member Mode updateAll package =
  +        if updateAll then
  +            UpdateAll
  +        else
  +            match package with
  +            | None -> Install
  +            | Some package -> SelectiveUpdate package
  +
   let selectiveUpdate resolve lockFile dependenciesFile updateAll package =
       let install () =
           let changedDependencies = DependencyChangeDetection.findChangesInDependenciesFile(dependenciesFile,lockFile)
  
positive.code:         | l -> l
  
      let getVersion pr =
          if updateAll then
              id
          else
              match exclude with
              | None -> skipVersions pr
              | Some package -> id
  
      let lockFile = selectiveUpdate (fun d p -> d.Resolve(getVersion, force, p, requirements)) oldLockFile dependenciesFile updateAll exclude
      lockFile.Save()
  
negative.code:         { ResolvedPackages = Resolution.Ok(resolution); ResolvedSourceFiles = lockFile.SourceFiles }
  
      let resolution =
          match UpdateMode.Mode updateAll package with
          | UpdateAll -> resolve dependenciesFile None
          | Install -> install ()
          | SelectiveUpdate p -> selectiveUpdate p
  
      LockFile(lockFile.FileName, dependenciesFile.Options, resolution.ResolvedPackages.GetModelOrFail(), resolution.ResolvedSourceFiles)
  
  