NuGet.PackageBuilder.RequiresV4TargetFrameworkSchema C# (CSharp) Method

        private static bool RequiresV4TargetFrameworkSchema(ICollection<IPackageFile> files)
        {
            // check if any file under Content or Tools has TargetFramework defined
            bool hasContentOrTool = files.Any(
                f => f.TargetFramework != null &&
                     (f.Path.StartsWith(Constants.ContentDirectory + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase) ||
                      f.Path.StartsWith(Constants.ToolsDirectory + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase)));

            if (hasContentOrTool)
            {
                return true;
            }

            // now check if the Lib folder has any empty framework folder
            bool hasEmptyLibFolder = files.Any(
                f => f.TargetFramework != null &&
                     f.Path.StartsWith(Constants.LibDirectory + Path.DirectorySeparatorChar, StringComparison.OrdinalIgnoreCase) &&
                     f.EffectivePath == Constants.PackageEmptyFileName);

            return hasEmptyLibFolder;
        }