I would like to overload a member of a class/structure in Python/C++ using pybind.

A minimal code example looks would be

#include <iostream>
#include <string>
#include <vector>
#include <pybind11/pybind11.h>
#include <pybind11/stl.h>
#include <pybind11/complex.h>
#include <pybind11/functional.h>
#include <pybind11/chrono.h>
#include <memory>
#include <cctype>

namespace py = pybind11;

struct Example {
    Example(){
        some_names = {"Marc", "Felix"};
    }

    int someFunction(const int& param) {
        return param;
    }

    int someOverloadedFunction(const float& param) {
        return static_cast< int >(param);
    }

    float someOverloadedFunction(const int& param) {
        return static_cast< float >(param);
    }    
    //++++++++ Variables ++++++++
    std::vector<std::string> some_names;
};

PYBIND11_MODULE(example, m) {
    m.doc() = "Example to be integrated into the main elements.";
    py::class_<Example>(m, "Example")
        .def(py::init<>())
        .def("someFunction",    &Example::someFunction)
        // Version 1 (Working): Use Overload Cast
        // .def("someOverloadedFunction", py::overload_cast< const int& >( &Example::someOverloadedFunction)) //  py::const_
        // .def("someOverloadedFunction", py::overload_cast< const float&>( &Example::someOverloadedFunction)); //  py::const_
        // Version 2 (Not working): Use Lambda Functions; 
        .def("someOverloadedFunction", [](const int &a){return &Example::someOverloadedFunction(a); })
        .def("someOverloadedFunction", [](const float &a){return &Example::someOverloadedFunction(a); });
}

// Run with:
// c++ -O3 -Wall -shared -std=c++14 -fPIC $(python3 -m pybind11 --includes) minimal_example.cpp -o minimal_example$(python3-config --extension-suffix)

While the overload_cast is working, it was recommended to use lambda functions. However, the Example::someOverloadedFunction is not found in this example and I assume, the reason is, that Example was not initialized here.

Error:

minimal_example.cpp:43:96: error: cannot call member function ‘float Example::someOverloadedFunction(const int&)’ without object
   43 |         .def("someOverloadedFunction", [](const int &a){return &Example::someOverloadedFunction(a); })

How do I do it the correct way?