public void doesNotContain(@Nullable CharSequence string) {
    checkNotNull(string);
    if (actual == null) {
      failWithActual("expected a string that does not contain", string);
    } else if (actual.contains(string)) {
      failWithActual("expected not to contain", string);
    }
  }
@Test
  public void stringDoesNotContainCharSequence() {
    CharSequence charSeq = new StringBuilder("d");
    assertThat("abc").doesNotContain(charSeq);
  }