func TestMax() {
	s1 := []int{1, 2, 3, -5}
	if got, want := a.SliceMax(s1), 3; got != want {
		panic(fmt.Sprintf("a.Max(%v) = %d, want %d", s1, got, want))
	}

	s2 := []string{"aaa", "a", "aa", "aaaa"}
	if got, want := a.SliceMax(s2), "aaaa"; got != want {
		panic(fmt.Sprintf("a.Max(%v) = %q, want %q", s2, got, want))
	}

	if got, want := a.SliceMax(s2[:0]), ""; got != want {

		if f(v) {
			r = append(r, v)
		}
	}
	return r
}

// Max returns the maximum element in a slice of some ordered type.
// If the slice is empty it returns the zero value of the element type.
func SliceMax[Elem Ordered](s []Elem) Elem {
	if len(s) == 0 {
		var zero Elem
		return zero
	}
	return Reduce(s[1:], s[0], Max[Elem])
}

// Min returns the minimum element in a slice of some ordered type.