protected function getFlags(): ?int
	{
		if($this->version === null)
		{
			return null;
		}

		switch($this->version)
		{
			case 'v4':
				return FILTER_FLAG_IPV4;
			case 'v6':
				return FILTER_FLAG_IPV6;
			default:
				throw new RuntimeException(vsprintf('Invalid IP version [ %s ]. The accepted versions are v4 and v6.', [$this->version]));
		}
	}