assertEquals("cat", anyOf("ab").trimFrom("abacatbab"));
  }

  private void doTestTrimFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'
    assertEquals(out, is('-').trimFrom(in));
    assertEquals(out, is('-').or(is('#')).trimFrom(in));
    assertEquals(out, isNot('x').trimFrom(in));
    assertEquals(out, is('x').negate().trimFrom(in));

    assertEquals("cat", anyOf("ab").trimFrom("abacatbab"));
  }

  private void doTestTrimFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'
    assertEquals(out, is('-').trimFrom(in));
    assertEquals(out, is('-').or(is('#')).trimFrom(in));
    assertEquals(out, isNot('x').trimFrom(in));
    assertEquals(out, is('x').negate().trimFrom(in));

   *
   * {@snippet :
   * CharMatcher.anyOf("ab").trimFrom("abacatbab")
   * }
   *
   * ... returns {@code "cat"}.
   *
   * <p>Note that:
   *
   * {@snippet :
   * CharMatcher.inRange('\0', ' ').trimFrom(str)
   * }
   *
   * ... is equivalent to {@link String#trim()}.
   */
  public String trimFrom(CharSequence sequence) {
    int len = sequence.length();
    int first;

  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");