};
    ListMultimap<String, String> transformed = Multimaps.transformEntries(multimap, transformer);
    assertEquals(ImmutableListMultimap.of("a", "a1", "a", "a4", "a", "a4", "b", "b6"), transformed);
    assertThat(transformed.toString()).isEqualTo("{a=[a1, a4, a4], b=[b6]}");
  }

  @J2ktIncompatible // Synchronized
  public void testSynchronizedMultimapSampleCodeCompilation() {