code: public final @NotNull S isNotIn(@NotNull Collection<?> values) {
      checkNotNull(values);
      if (!isActualIn(values)) {
        return myself();
      }
      failIfCustomMessageIsSet();
      throw failure(unexpectedIn(actual, values));
    }
docs: Verifies that the actual value is in the given collection.
  
  @param values the given collection to search the actual value in. must not be null.
  @return this assertion object.
  @throws AssertionError       if the actual value is not in the given collection.
  @throws NullPointerException if the given collection is null.