Why function is static in python?

Why function is static in python?

If we want to integrate C/C++ into python using internal Python API. Then
signature of functions are in the following forms
static PyObject *MyFunction( PyObject *self, PyObject *args );
static PyObject *MyFunctionWithKeywords(PyObject *self,
PyObject *args,
PyObject *kw);
static PyObject *MyFunctionWithNoArgs( PyObject *self );
Why these functions are implemented as static?