hello_ext_123.c

#include "Python.h"

PyObject* get_message(PyObject* self, PyObject* args) {
  PyObject* message = PyUnicode_FromString("hello from extension");
  return message;
}

static PyMethodDef hello_methods[] = {
    {"get_message",
     get_message,
     METH_NOARGS,
     "Get a generic hello message"},
    {NULL, NULL, 0, NULL}};

static PyModuleDef hello_module = {
    PyModuleDef_HEAD_INIT,
    "hello",
    .m_size = -1,
    .m_methods = hello_methods,
    .m_free = NULL,
};

PyMODINIT_FUNC PyInit_hello_ext_123() {
  PyObject* module = PyModule_Create(&hello_module);
  return module;
}