code: public static <T extends Case1<A>, A> DecomposableMatchBuilder1<T, A> case1(
        Class<T> clazz, MatchesAny<A> a) {
      List<Matcher<Object>> matchers = Lists.of(ArgumentMatchers.any());
      return new DecomposableMatchBuilder1<T, A>(matchers, 0, new Case1FieldExtractor<>(clazz));
    }
docs: Matches a case class of one element.
  
  <p>If matched, the {@code a} value is extracted.