How to support Prod observables in custom devices? about pennylane HOT 3 OPEN

class ProdPatch(qml.operation.Observable):

    def __init__(self, prod_op):
        self.prod_op = prod_op

    @property
    def name(self):
        return [op.name for op in self.prod_op]

    @property
    def parameters(self):
        return self.prod_op.parameters

    @property
    def wires(self):
        return self.prod_op.wires

class MyDevice(Device):
    author = "Christian Gogolin"
    pennylane_requires = ">=0.29.1"
    name = "MyDevice"
    short_name = "my.device"
    version = "0.1.0"

    _capabilities = {
        "tensor_observables": True,
    }

    @property
    def observables(self):
        return ["PauliZ", "Prod"]

    def supports_observable(self, observable):
        if isinstance(observable, list):
            return all(self.supports_observable(ob) for ob in observable)
        return super().supports_observable(observable)
    
    def execute(self, queue, observables, parameters=None, **kwargs):
        new_measurements = []
        for mp in observables:
            if mp.obs and isinstance(mp.obs, qml.ops.Prod):
                new_measurements.append( type(mp)(obs=ProdPatch(mp.obs)) )
            else:
                new_measurements.append(mp)
        return super().execute(queue, new_measurements, parameters=parameters, **kwargs)
    
    def __init__(self, wires, *args, **kwargs):
        if wires != 2:
            raise NotImplementedError()
        self._state = None
        super().__init__(wires, *args, **kwargs)
    
    def apply(self, operation, wires, par):
        raise NotImplementedError(f"operation={operation}")

    def expval(self, observable, wires, par):
        if isinstance(observable, list):
            observables = observable
            for observable in observables:
                if observable != "PauliZ":
                    raise NotImplementedError()
            return np.prod([self.expval(observable, wire, par) for observable, wire in zip(observables, wires)])

        if observable != "PauliZ":
            raise NotImplementedError()
        return float(np.real(np.dot(self._state.conj().T, qml.matrix(qml.PauliZ(wires), wire_order=qml.wires.Wires([0, 1])).dot(self._state))).item())

    @property
    def operations(self):
        return []

    def reset(self):
        self._state = np.array([1., 0., 0., 0.])