public function extensions()
    {
        $extensions = $this->getRequiredExtensions();
        $missing = array_filter($extensions, function ($extension) {
            return !$this->checkExtension($extension);
        });

        if ($missing) {
            $this->explainer->error('Extensions mission from server: '.implode(', ', $missing));
        }

        return count($missing) === 0;
    }