code: def expected_grad_fidelity_rx_pauliz(param):
      """Return the analytical gradient of the fidelity for the RX and PauliZ."""
      return -np.sin(param) / 2
  
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: expected_grad_fidelity_rx_pauliz(param) and returns: unknown