An example of python boost use for a python - C++ interface utilizing python lists as arguments

drow.cpp

#include <boost/python.hpp>
#include <string>

namespace py = boost::python;

class drow{
    public:
        std::string word;
        drow(std::string word): word(word){};
        drow(py::list ch);
        py::list get_chars();
};

drow::drow(py::list l){
    std::string w {""};
    std::string gap {" "};
    std::string token;
    for (int i = 0; i < len(l) ; i++){
        token = py::extract<std::string>(l[i]);
        if (i == len(l) -1){
            w += token;
            break;
        }
        w += token + gap;
    }
    this -> word = w;
}

py::list drow::get_chars(){
    py::list char_vec;
    for (auto c : word){
        char_vec.append(c);
    }
    return char_vec;
}


BOOST_PYTHON_MODULE(drow){
    py::class_<drow>("drow", py::init<std::string>())
        .def(py::init<py::list>())
        .def("get_chars", &drow::get_chars)
        .def_readwrite("word", &drow::word);
}

Makefile

drow.so:                                                                                                           
    g++ -Wall -shared -fPIC -o drow.so drow.cpp -std=c++0x -lboost_python -I/usr/include/python2.7

use_drow.py

from drow import drow

# create drow instance
d = drow('dog')

# access the word and print it
print d.word

# print the chars
for char in d.get_chars():
    print char

# check out if it works for a list
# it will join the words and save them in word variable
d = drow(['cat', 'dog', 'canary'])

# print me joined
print d.word

Sorry, only just came across this comment by chance. It's been a long time since I looked into this, maybe you could find something here: http://www.boost.org/doc/libs/1_59_0/libs/python/doc/v2/reference.html

I actually worked on a similar bit of code today - example with size_t :

class text {
    ...
    size_t length();
};

class_<text>("Text", init<std::string>())
    .def("__len__", &text::length)
;

It is a nice tutorial, excellent to beginning.