@Test
 public void shouldRecognizeApplicabilityToTypes() {
   final Function5<Integer, Integer, Integer, Integer, Integer, Integer> f =
       (i1, i2, i3, i4, i5) -> null;
   assertThat(
           f.isApplicableToTypes(
               Integer.class, Integer.class, Integer.class, Integer.class, Integer.class))
       .isTrue();
 }