The following code example is taken from the book
C++17 - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2017
The code is licensed under a Creative Commons Attribution 4.0 International License. Creative Commons License

// raw code

// "inherit" all function call operators of passed base types:
template<typename... Ts>
struct overload : Ts...
  using Ts::operator()...;

// base types are deduced from passed arguments:
template<typename... Ts>
overload(Ts...) -> overload<Ts...>;