demo.c

#include <stdio.h>
#include <Python.h>


int addition (int a, int b) { 

  return a+b; 
}


// sum of two number
static PyObject* DemoLib_addition(PyObject *self, PyObject *args) {
   int a;
   int b;
   if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
      return NULL;
   }
   
 return Py_BuildValue("i", addition(a,b));
}

// module's function table
static PyMethodDef demoMethods[] ={
     {"addition", DemoLib_addition, METH_VARARGS, "sum of two number"},
     {NULL, NULL, 0, NULL}
};

static struct PyModuleDef demomodule = {
  PyModuleDef_HEAD_INIT,
  "demo",
  NULL, 
  -1,
  demoMethods
};

PyMODINIT_FUNC
PyInit_demo(void)
{
  Py_Initialize();
  return PyModule_Create(&demomodule);
}

sample.py

import demo
# kütüphane yükleyelim 

a,b=int(input()),int(input()) 
result=addition(a,b) 
print("toplam ",result)

setup.py

from setuptools import Extension, setup

module = Extension("demo",
                  sources=[
                    'demo.c'
                  ])
setup(name='demo',
     version='1.0',
     description='example demo package',
     ext_modules=[module])