hello.c

#include <Python.h>

PyObject *hello(PyObject *self, PyObject *args) {
    printf("Hello World\n");
    Py_RETURN_NONE;
}

struct PyMethodDef greeter_methods[] = {
    {"hello", hello, METH_NOARGS, "Some docs..."},
    {NULL, NULL, 0, NULL}
};

struct PyModuleDef greeter = {
    PyModuleDef_HEAD_INIT,
    "greeter",
    "It's just docs",
    -1,
    greeter_methods
};

PyMODINIT_FUNC PyInit_greeter(void) {
   return PyModule_Create(&greeter);
}