public function getInstances()
    {
        if (null === $this->instances) {
            $this->instances = [];

            foreach ($this->getAll() as $className) {
                $className = '\\PHPSemVer\\Trigger\\' . str_replace('/', '\\', $className);

                $this->instances[] = new $className();
            }
        }

        return $this->instances;
    }