python解释器如何实现字典合并

// 实现字典合并生成新字典的逻辑，对应于 | 操作符
static PyObject *
dict_or(PyObject *self, PyObject *other)
{
    if (!PyDict_Check(self) || !PyDict_Check(other)) {
        Py_RETURN_NOTIMPLEMENTED;
    }
    PyObject *new = PyDict_Copy(self);
    if (new == NULL) {
        return NULL;
    }
    if (dict_update_arg(new, other)) {
        Py_DECREF(new); // 减少引用计数
        return NULL;
    }
    return new;
}
 
// 实现字典就地合并逻辑，对应于 |= 操作符
static PyObject *
dict_ior(PyObject *self, PyObject *other)
{
    if (dict_update_arg(self, other)) {
        return NULL;
    }
    Py_INCREF(self); // 增加引用计数
    return self;
}