How can I pass a lambda/std::function/Functor to a variadic function

Question

I have a variadic function like this:

template <class... PickComponents, size_t... PickComponentIndices>
void iterateEntitiesInternal(
  const std::function<void(Entity, const PickComponents &...)> &iterFn,
  std::index_sequence<PickComponentIndices...> sequence
);

template <class... PickComponents>
void iterateEntities(const std::function<void(Entity, const PickComponents &...)> &iterFn) {
  iterateEntitiesInternal(iterFn, std::index_sequence_for<PickComponents...>{});
}

I want to be able to call the function like this:

iterateEntities<A, B, C>([](Entity entity, const auto &c1, const auto &c2, const auto &c3) {
  // ...
});

Is there a way I can make this work? I tried creating a template structure like:

template <typename T> struct IterFnType { typedef T type; };

and using it like this:

template <class... PickComponents>
void iterateEntities(const typename IterFnType<std::function<void(Entity, const PickComponents &...)>>::type &iterFn);

But it gives me a compiler error in GCC:

error: ‘typename liquid::EntityStorageSparseSet::IterFnType’ names ‘template<class ... ComponentTypes> template struct liquid::EntityStorageSparseSet::IterFnType’, which is not a type

What is the correct way of passing lambdas to variadic functions?