VersionPress\Storages\Serialization\IniSerializer::serializeKeyValuePair PHP Method

    private static function serializeKeyValuePair($key, $value)
    {
        if (is_null($value)) {
            $value = self::$nullValue;
        } elseif (is_string($value)) {
            $value = '"' . self::escapeString($value) . '"';
        }
        return $key . " = " . $value;
    }