Iterable<Long> convertedValues = STR_TO_LONG.convertAll(STRINGS);
    assertEquals(LONGS, ImmutableList.copyOf(convertedValues));
  }

  public void testConvertAllIsView() {
    List<String> mutableList = Lists.newArrayList("789", "123");
    Iterable<Long> convertedValues = STR_TO_LONG.convertAll(mutableList);
    assertEquals(ImmutableList.of(789L, 123L), ImmutableList.copyOf(convertedValues));

   * B>`, convertAll could accept and return iterables with nullable element types. In both cases,
   * we've chosen to instead use a signature that benefits existing users -- and is still safe.
   *
   * For convertAll, I haven't looked as closely at *how* much existing users benefit, so we should
   * keep an eye out for problems that new users encounter. Note also that convertAll could support