code: public static <A, EA extends A, A1, A2, A3> DecomposableMatchBuilder3<Tuple1<A>, A1, A2, A3> tuple1(
        DecomposableMatchBuilder3<EA, A1, A2, A3> a) {
      List<Matcher<Object>> matchers = Lists.of(ArgumentMatchers.any());
      return new DecomposableMatchBuilder1<Tuple1<A>, EA>(matchers, 0, new Tuple1FieldExtractor<>())
          .decomposeFirst(a);
    }
docs: Matches a tuple of 1 element.
  
  <p>If matched, the {@code a} value is decomposed to 3.