anchor.diff:              | Some f -> 
                   let refFile = ReferencesFile.FromFile f
                   refFile.Groups
  -                |> Seq.map (fun kv -> kv.Value.NugetPackages |> List.map (fun p -> kv.Key, p, false))
  +                |> Seq.map (fun kv -> kv.Value.NugetPackages |> List.map (fun p -> Some kv.Key, p))
                   |> List.concat
               | None -> []
             
  
positive.code:                             not nuspec.IsDevelopmentDependency
                      with
                      | _ -> true)
              |> List.map (fun (groupName,np, isReferencedProject) ->
                      let dependencyVersionRequirement =
                          if not lockDependencies then
                              match dependencies.Groups |> Map.tryFind groupName with
  
negative.code:                     let dep =
                          match dependencyVersionRequirement with
                          | Some installed -> installed
                          | None -> failwithf "No package with id '%A' installed in group %O." np.Name groupName
                      np.Name, dep)
          deps |> List.fold addDependency withDepsAndIncluded
  