code: protected static void failIfActualIsNull(@Nullable String customErrorMessage, @Nullable Description description,
                                             @Nullable Object actual) {
      if (actual != null) {
        return;
      }
      failWithMessage(customErrorMessage);
      fail(description, array("expecting actual value not to be null"));
    }
docs: Throws an {@code AssertionError} if the actual value is {@code null}.
  
  @param customErrorMessage any custom error message. This message will replace the default one only if it (the
  custom message) is not {@code null}.
  @param description        the description of the actual value.
  @param actual             the actual value.
  @throws AssertionError if the actual value is {@code null}.
  @since 1.3