class_docstr: Tests for Fidelity function between two QNodes.
docstr: Test that fidelity is correct with custom wire labels
code: def test_fidelity_wire_labels(self, device, tol):
      """Test that fidelity is correct with custom wire labels"""
      param = np.array([0.678, 1.234])
      wires = ["a", 8]
      dev = qml.device(device, wires=wires)
  
      @qml.qnode(dev)
      def circuit(x):
          qml.PauliX(wires=wires[0])
          qml.IsingXX(x, wires=wires)
          return qml.state()
  
      fid_circuit = qml.qinfo.fidelity(
          circuit, circuit, [wires[0]], [wires[1]]
      )
      actual = fid_circuit((param[0],), (param[1],))
  
      expected = (
          np.sin(param[0] / 2) * np.cos(param[1] / 2)
          + np.sin(param[1] / 2) * np.cos(param[0] / 2)
      ) ** 2
      assert np.allclose(actual, expected, atol=tol)
  
imports: import pytest
  import pennylane
  from pennylane import numpy
label_desc: Use image node_id 9 for calling the TestFidelityQnode obj's underlying member method code with example usage: obj.test_fidelity_wire_labels(device, tol) and returns: qml