class_docstr: Test the private helpers for preprocessing.
class_docstr_tok: ["Test","the","private","helpers","for","preprocessing","."]
code: def decomposer(op):
      return op.decomposition()
  
imports: import pytest
  import pennylane
  from pennylane.operation import Operation
  from pennylane.tape import QuantumScript
  from pennylane import DeviceError
  from pennylane.devices.preprocess import no_sampling, validate_device_wires, validate_multiprocessing_workers, validate_adjoint_trainable_params, _operator_decomposition_gen, decompose, validate_observables, validate_measurements
label_desc: Use image node_id 1 for calling the TestPrivateHelpers obj's underlying member method code with example usage: obj.decomposer(op) and returns: op