@SuppressWarnings("NullAway")
  protected final @PolyNull V copyValue(@PolyNull Expirable<V> expirable) {
    if (expirable == null) {
      return null;
    }
    V copy = copier.copy(expirable.get(), cacheManager.getClassLoader());
    return requireNonNull(copy);
  }
@Test
  public void copyValue_null() {
    assertThat(jcache.copyValue(null)).isNull();
  }