qs, err := FooStore.GetM("a").GetM("b").GetM("c").Do(ctx)
// get results as slice, same order as inputs
qs.GetSlice() // return slice {"a", "b", "c"}

qs, err := FooStore.GetM("b").GetM("c").GetM("a").Do(ctx)
// get results as slice, same order as inputs
qs.GetSlice() // return slice {"b", "c", "a"}

// get single result
v, err := qs.Get("a")
v, err := qs.Get("b")
// not exist, err != nil
v, err := qs.Get("q")