Pass function from python to C++ and then execute using that function defintion

[behzadtabari]

Problem description
Since I want the objective function user-defined I need to pass a function declaration and definition from Python to C++ and then I need to use that function in another object member function which takes in the function argument, when I try to implement it as below I get the following error, I am completely stuck and I do not even know where to look for it to understand if it is feasible to use this feature in Pybind11

opt.optimize(myfunc)
TypeError: optimize(): incompatible function arguments. The following argument types are supported:
    1. (self: some_name.NLOptOptimizer) -> None

Invoked with: <some_name.NLOptOptimizer object at 0x7ff5c799c070>, <function myfunc at 0x7ff5cd198dc0>

Reproducible example code
c++ wrapping and definitions

int NLOptOptimizer::Optimize(const std::function<double(const std::vector<double> &x, std::vector<double>& grad, void* data)> *objective_function){ 
                           
  nlopt::opt opt("LD_MMA", 2);
  std::vector<double> lb(2);
  lb[0] = -HUGE_VAL; lb[1] = 0;
  opt.set_lower_bounds(lb);
   // this is where I am supposed to give the objective function to another member function of an object 
  opt.set_min_objective(objective_function, NULL);

py::class_<NLOptOptimizers>(m, "NLOptOptimizer")
        .def(py::init<>())
        .def("optimize", &NLOptOptimizer::Optimize);

import some_name 
import numpy as np


def myfunc(x, grad,data):
    if grad.size > 0:
        grad[0] = 0.0
        grad[1] = 0.5 / np.sqrt(x[1])
    return np.sqrt(x[1])


opt = some_name.NLOptOptimizer()
opt.optimize(myfunc)