public void doesNotContain(@Nullable Object rowKey, @Nullable Object columnKey) {
    if (checkNotNull(actual).contains(rowKey, columnKey)) {
      failWithoutActual(
          simpleFact("expected not to contain mapping for row-column key pair"),
          fact("row key", rowKey),
          fact("column key", columnKey),
          fact("but contained value", actual.get(rowKey, columnKey)),
          fact("full contents", actual));
    }
  }
@Test
  public void doesNotContain() {
    ImmutableTable<String, String, String> table = ImmutableTable.of("row", "col", "val");
    assertThat(table).doesNotContain("row", "row");
    assertThat(table).doesNotContain("col", "row");
    assertThat(table).doesNotContain("col", "col");
    assertThat(table).doesNotContain(null, null);
  }