public function isDefault()
    {
        if ($this->getAttribute()->hasOption(UuidAttribute::OPTION_DEFAULT_VALUE)
            && $this->getAttribute()->getOption(UuidAttribute::OPTION_DEFAULT_VALUE) !== 'auto_gen'
        ) {
            return $this->sameValueAs($this->getAttribute()->getDefaultValue());
        }

        throw new RuntimeException(
            'Operation not supported. A new UUIDv4 is generated for every getNullValue call. No default value set.'
        );
    }