protected function getConstantValues(string $classIdentifier, string $regex) : array
    {
        $reflectionClass = new \ReflectionClass($classIdentifier);
        $constants = $reflectionClass->getConstants();

        $validValues = array_filter($constants, function ($constantName) use ($regex) {
            return preg_match($regex, $constantName);
        }, ARRAY_FILTER_USE_KEY);

        return $validValues;
    }