void write_json_helper(std::basic_ostream<typename Ptree::key_type::value_type> &stream, 
                           const Ptree &pt,
                           int indent, bool pretty)
    {

        typedef typename Ptree::key_type::value_type Ch;
        typedef typename std::basic_string<Ch> Str;

        // Value or object or array
        if (indent > 0 && pt.empty())
        {
            // Write value
            Str data = create_escapes(pt.template get_value<Str>());
            stream << Ch('"') << data << Ch('"');

        }
        else if (indent > 0 && pt.count(Str()) == pt.size())
        {
            // Write array
            stream << Ch('[');
            if (pretty) stream << Ch('\n');
            typename Ptree::const_iterator it = pt.begin();
            for (; it != pt.end(); ++it)
            {
                if (pretty) stream << Str(4 * (indent + 1), Ch(' '));
                write_json_helper(stream, it->second, indent + 1, pretty);
                if (lslboost::next(it) != pt.end())
                    stream << Ch(',');
                if (pretty) stream << Ch('\n');
            }
            stream << Str(4 * indent, Ch(' ')) << Ch(']');

        }
        else
        {
            // Write object
            stream << Ch('{');
            if (pretty) stream << Ch('\n');
            typename Ptree::const_iterator it = pt.begin();
            for (; it != pt.end(); ++it)
            {
                if (pretty) stream << Str(4 * (indent + 1), Ch(' '));
                stream << Ch('"') << create_escapes(it->first) << Ch('"') << Ch(':');
                if (pretty) {
                    if (it->second.empty())
                        stream << Ch(' ');
                    else
                        stream << Ch('\n') << Str(4 * (indent + 1), Ch(' '));
                }
                write_json_helper(stream, it->second, indent + 1, pretty);
                if (lslboost::next(it) != pt.end())
                    stream << Ch(',');
                if (pretty) stream << Ch('\n');
            }
            if (pretty) stream << Str(4 * indent, Ch(' '));
            stream << Ch('}');
        }

    }