让我们来看看：
import disdis.dis(lambda: print_arg(**{'key': 'value'})) 60 LOAD_GLOBAL 0 (print_arg) 3 BUILD_MAP 1 6 LOAD_ConST 1 ('value') 9 LOAD_ConST 2 ('key') 12 STORE_MAP 13 CALL_FUNCTION_KW 0 16 RETURN_VALUE让我们找出
CALL_FUNCTION_KW（
ceval.c）的作用：
case CALL_FUNCTION_VAR: case CALL_FUNCTION_KW: case CALL_FUNCTION_VAR_KW: { // ... x = ext_do_call(func, &sp, flags, na, nk); // ...static PyObject *ext_do_call(PyObject *func, PyObject ***pp_stack, int flags, int na, int nk){ int nstar = 0; PyObject *callargs = NULL; PyObject *stararg = NULL; PyObject *kwdict = NULL; PyObject *result = NULL; if (flags & CALL_FLAG_KW) { // if ** is involved kwdict = EXT_POP(*pp_stack); // get the dict passed with ** if (!PyDict_Check(kwdict)) { PyObject *d; d = PyDict_New(); // make a NEW dict if (d == NULL) goto ext_call_fail; if (PyDict_Update(d, kwdict) != 0) { // update it with old // .. fail .. goto ext_call_fail; } Py_DECREF(kwdict); kwdict = d; // kwdict is now the new dict } } .... result = PyObject_Call(func, callargs, kwdict); // call with new dict
