private function getRenderer(string $template): string
    {
        if (is_readable($template) === false) {
            throw new View\Exception('Could not open file "' . basename($template) . '"');
        }

        $suffix = strtolower(pathinfo($template, PATHINFO_EXTENSION));

        if (isset($this->renderer[$suffix]) === false) {
            throw new View\Exception('No template engine registered for file extension "' . $suffix . '"');
        }

        return $this->renderer[$suffix];
    }