How to derive from a variadic template class in C++

I have variadic template class which is just a wrapper for std::tuple :

    template <typename ... Child>
    class Tpl
    {
    public:
        Tpl() {}
        Tpl(Child ...args) : child(args...)
        {}

        template <typename T>
        T& Get()
        {
            return std::get<T>(child);
        }

        template <typename T>
        const T& GetConst()
        {
            return std::get<T>(child);
        }
    private:
        std::tuple<Child ...> child;
    };

How do I correctly derive a class from Tpl?

    template <typename... Ts>
    class SomeObject : public Tpl<Ts...>
    {
    public:
        Some(/*Types ... args*/) /*: child(args...)*/
        {

        }
    private:
        int num;        
    };

The compiler message just tells me: "syntax error: missing ',' before '<' in the line: class DbgGameObject : public Tpl

Thanks for your help!