public function getCascadeOption($cascadeValue)
    {
        $defaultCascade = $this->getRegistry()->config->get(static::CFG_DEFAULT_CASCADE);
        if (empty($cascadeValue) && !empty($defaultCascade)) {
            return [$defaultCascade];
        }

        /** @var Validator $validator */
        $validator = $this->getRegistry()->validator->get(static::CFG_DEFAULT_CASCADE);

        $cascadeValue = array_map('strtolower', array_map('trim', explode(',', $cascadeValue)));
        $cascadeValue = array_intersect($cascadeValue, $validator->getChoices());
        $cascadeValue = array_filter($cascadeValue);
        if(empty($cascadeValue)) {
            return null;
        }

        return $cascadeValue;
    }