dev = qml.device('lightning.qubit', wires=2)

@qml.qnode(dev, diff_method="adjoint")
def circuit(x):
    qml.RX(x, wires=0)
    return qml.expval(qml.s_prod(2.0, qml.PauliZ(0)))

x = qml.numpy.array(1.0)

circuit(x)

File ~/Prog/pennylane-lightning/pennylane_lightning/_serialize.py:66, in _obs_has_kernel(ob)
     57 def _obs_has_kernel(ob: Observable) -> bool:
     58     """Returns True if the input observable has a supported kernel in the C++ backend.
     59 
     60     Args:
   (...)
     64         bool: indicating whether ``obs`` has a dedicated kernel in the backend
     65     """
---> 66     if is_pauli_word(ob):
     67         return True
     68     if isinstance(ob, (Hadamard, Projector)):

File ~/Prog/pennylane/pennylane/grouping/utils.py:77, in is_pauli_word(observable)
     53 """
     54 Checks if an observable instance is a Pauli word.
     55 
   (...)
     73 False
     74 """
     76 if not isinstance(observable, Observable):
---> 77     raise TypeError(f"Expected {Observable} instance, instead got {type(observable)} instance.")
     79 pauli_word_names = ["Identity", "PauliX", "PauliY", "PauliZ"]
     80 if isinstance(observable, Tensor):

TypeError: Expected <class 'pennylane.operation.Observable'> instance, instead got <class 'pennylane.ops.op_math.sprod.SProd'> instance.