anchor.diff:                              group.ReplaceFramework(
                                   framework,
                                   (fun _ -> { References = newFiles; ContentFiles = Set.empty }),
  -                                (fun files -> files),
  -                                (fun _ -> Some({ References = newFiles; ContentFiles = Set.empty })))),
  +                                (fun files -> files))),
                           (fun _ -> Some(FrameworkGroup.singleton(framework,{ References = newFiles; ContentFiles = Set.empty }))))) this
       
       member this.UseLastInGroupAsFallback() = 
  
positive.code:                 group.ReplaceFramework(
                      framework,
                      (fun _ -> InstallFiles.empty.AddFrameworkAssemblyReference assemblyName),
                      (fun files -> files.AddFrameworkAssemblyReference assemblyName),
                      (fun _ -> Some (InstallFiles.empty.AddFrameworkAssemblyReference assemblyName)))),
              (fun _ -> None))
      
      member this.AddFrameworkAssemblyReferences(references) : InstallModel = 
  
negative.code:                 group.ReplaceFramework(
                      framework,
                      (fun _ -> InstallFiles.singleton lib),
                      (fun files -> files.AddReference lib))),
              (fun _ -> Some(FrameworkGroup.singleton(framework,InstallFiles.singleton lib))))
  
      member this.AddReferences(libs, references) : InstallModel = 
  