How to receive a return value from python correctly? #259

/// Test 1: Python Class
    qDebug() << "Test 1: Python Class";
    {
        QVariant pyobj = context.evalScript("TestPyObj()", Py_eval_input); /// The TestPyObj Class is defined by Python Code
        qDebug() << pyobj;
        if(pyobj.isValid()) {
            PythonQtObjectPtr pyobj_ptr(pyobj);
            qDebug() << "PyObj RefCount:" << pyobj_ptr->ob_refcnt; ///2 pyobj & pyobj_ptr
            pyobj.clear();
            qDebug() << "PyObj RefCount:" << pyobj_ptr->ob_refcnt; ///1 pyobj
            pyobj_ptr.call("print");
        }
        /// destroyed
    }

///... init code

PythonQt::self()->registerCPPClass("TestCppObj", "", "TestUtils", PythonQtCreateObject<TestCppObjWrapper>, PythonQtSetInstanceWrapperOnShell<TestCppObjShell>);

///... other code

qDebug() << "Test 2: C++ Class";
    {
        QVariant pyobj = context.evalScript("pqt.TestUtils.TestCppObj()", Py_eval_input);
        qDebug() << pyobj;
        if(pyobj.isValid()) {
            
        }
    }

/// Class 
class TestCppObj {
    public:
        TestCppObj() {
            std::cout << "TestCPPObj created " << size_t(this) << std::endl;
        }
        virtual ~TestCppObj() {
            std::cout << "TestCPPObj destroyed " << size_t(this) << std::endl;
        }
    
        virtual void print() {
            std::cout << "Hello from C++" << std::endl;
        }
};

/// Shell Class
class TestCppObjShell : public TestCppObj {
public:
    TestCppObjShell(): _wrapper(nullptr) {
        std::cout << "TestCppObjShell created " << size_t(this) << std::endl;
    }
    ~TestCppObjShell() {
        std::cout << "TestCppObjShell destroyed " << size_t(this) << std::endl;
        PythonQtPrivate* priv = PythonQt::priv();
        if (priv) { priv->shellClassDeleted(this); }
    }

    void print() override {
        std::cout << "Shell Print" << std::endl;
        if (_wrapper) {
            PYTHONQT_GIL_SCOPE;
            if(((PyObject*)_wrapper)->ob_refcnt > 0) {
                static PyObject* name = PyString_FromString("print");
                PyObject* obj = PyBaseObject_Type.tp_getattro((PyObject*)_wrapper, name);
                if (obj) {
                    static const char* argumentList[] ={""};
                    static const PythonQtMethodInfo* methodInfo = PythonQtMethodInfo::getCachedMethodInfoFromArgumentList(1, argumentList);
                    void* args[1] = {nullptr};
                    PyObject* result = PythonQtSignalTarget::call(obj, methodInfo, args, true);
                    if (result) { Py_DECREF(result); }
                    Py_DECREF(obj);
                    return;
                } else {
                    PyErr_Clear();
                }
            }
        }
        TestCppObj::print();
    }
    PythonQtInstanceWrapper* _wrapper { nullptr };
};

/// Wrapper Class
class TestCppObjWrapper : public QObject {
    Q_OBJECT
public slots:
    TestCppObj* new_TestCppObj() {
        return new TestCppObjShell ();
    }

    void delete_TestCppObj(TestCppObj* obj) {
        delete obj;
    }

    void print(TestCppObj* obj) {
        obj->print();
    }
};