internal static INamespaceBuilder CreateNamespaceBuilderService(string extension, INamespaceAdjusterOptions options)
        {
            INamespaceBuilder rslt        = null;
            string            projectName = ProjectHelper.GetProjectExtensionName(extension);

            switch (projectName)
            {
            case Statics.CsProjectFileExtension:
                rslt = new CsNamespaceBuilderService(options);
                break;

            case Statics.VbProjectFileExtension:
                rslt = new VbNamespaceBuilderService(options);
                break;
            }

            if (rslt is null)
            {
                throw new Exception($"Unsupported project file '{projectName}'.");
            }

            return(rslt);
        }