private function updateSiteBundleLoader(MutableBag $contents)
    {
        if (!$this->io->confirm('Would you like to enable the default site Bundle?')) {
            return;
        }

        $extensions = (array) $contents->get('extensions', []);
        foreach ($extensions as $extension) {
            if (is_a($extension, CustomisationExtension::class, true)) {
                // If there is already a valid entry, exit
                return;
            }
        }
        // Add the extension to the bag
        $extensions[] = CustomisationExtension::class;
        $contents->set('extensions', $extensions);
    }