#include <type_traits>

template <typename...>
struct Pack { };

/* Implement Add_Type and Remove_Type */

int main()
{
    // Testing Add_Type
    {
        using Target = int;
        using Indata = Pack<float, bool>;
        using Answer = Pack<int, float, bool>;
        using Result = typename Add_Type<Target, Indata>::type;
        static_assert( std::is_same_v<Result, Answer> );
    }
    // No types to remove
    {
        using Target = int;
        using Indata = Pack<float, bool>;
        using Answer = Pack<float, bool>;
        using Result = typename Remove_Type<Target, Indata>::type;
        static_assert( std::is_same_v<Result, Answer> );
    }
    // One to remove, in the beginning
    {
        using Target = int;
        using Indata = Pack<int, float, bool>;
        using Answer = Pack<float, bool>;
        using Result = typename Remove_Type<Target, Indata>::type;
        static_assert( std::is_same_v<Result, Answer> );
    }
    // Multiple to remove, not in the beginning, other than int
    {
        using Target = float;
        using Indata = Pack<int, float, bool, float, float, int>;
        using Answer = Pack<int, bool, int>;
        using Result = typename Remove_Type<Target, Indata>::type;
        static_assert( std::is_same_v<Result, Answer> );
    }
}