anchor.diff:              |> Async.Parallel
               |> Async.RunSynchronously
               |> Seq.concat
  -            |> Seq.append currentPage
  +
  +        return
  +            entriesVersions
  +            |> Seq.append linksVersions
       }
   
   /// Gets versions of the given package via OData via /Packages?$filter=Id eq 'packageId'
  
positive.code:             | Some node -> node
              | None -> failwithf "unable to parse data from %s" url
  
          let currentPage = 
              feed |> getNode "entry" |> optGetNode "properties" |> optGetNode "Version" 
              |> Option.map (fun node -> node.InnerText)
              |> Option.toList
  
          return 
              feed 
              |> getNodes "link"
              |> List.filter (fun node -> node |> getAttribute "rel" = Some "next")
  
negative.code:     async { 
          // we cannot cache this
          try 
              let url = sprintf "%s/FindPackagesById()?id='%s'" nugetURL package
              return! followODataLink auth url
          with _ -> return! getAllVersionsFromNugetODataWithFilter (auth, nugetURL, package)
      }
  
  