class_docstr: Tests for the Trace Distance function between two QNodes.
docstr: Test that trace_distance is correct with custom wire labels
docstr_tok: ["Test","that","trace_distance","is","correct","with","custom","wire","labels"]
code: def test_trace_distance_wire_labels(self, device, tol):
      """Test that trace_distance 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()
  
      td_circuit = qml.qinfo.trace_distance(
          circuit, circuit, [wires[0]], [wires[1]]
      )
      actual = td_circuit((param[0],), (param[1],))
  
      expected = 0.5 * (
          np.abs(np.cos(param[0] / 2) ** 2 - np.sin(param[1] / 2) ** 2)
          + np.abs(
              np.cos(param[1] / 2) ** 2 - np.sin(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 4 for calling the TestTraceDistanceQnode obj's underlying member method code with example usage: obj.test_trace_distance_wire_labels(device, tol) and returns: qml