code: def qnode_4(x):
      return qml.expval(qml.PauliX(0))
  
imports: from inspect import signature
  from itertools import chain
  from functools import reduce
  import pytest
  import numpy
  import pennylane
  from pennylane import numpy
  from pennylane.fourier.reconstruct import _reconstruct_equ, _reconstruct_gen, _prepare_jobs, reconstruct
  from pennylane.fourier.utils import join_spectra
label_desc: Use image node_id 8 for calling a global function with example usage: qnode_4(x) and returns: qml