code: def _pw_prefactor_pauli(
      observable: Union[PauliX, PauliY, PauliZ, Identity]
  ):  # pylint:disable=unused-argument
      return 1
  
file_path: pennylane/pennylane/pauli/pauli_interface.py
imports: from typing import Union
  from functools import singledispatch
  from pennylane.ops import Hamiltonian, Identity, PauliX, PauliY, PauliZ, Prod, SProd
  from pennylane.operation import Tensor
  from .utils import is_pauli_word
  from .conversion import pauli_sentence
label_desc: Use image node_id 3 for calling a global function with example usage: _pw_prefactor_pauli(observable) and returns: int