class_docstr: Further unit tests for some new methods of QubitDevice.
class_docstr_tok: ["Further","unit","tests","for","some","new","methods","of","QubitDevice","."]
docstr: Tests that an error is raised when mutual information is measured
  with custom wire labels
docstr_tok: ["Tests","that","an","error","is","raised","when","mutual","information","is","measured","with","custom","wire","labels"]
code: def test_custom_wire_labels_error(self):
      """Tests that an error is raised when mutual information is measured
      with custom wire labels"""
      dev = qml.device("default.qubit.legacy", wires=["a", "b"])
  
      with qml.queuing.AnnotatedQueue() as q:
          qml.PauliX(wires="a")
          qml.mutual_info(wires0=["a"], wires1=["b"])
  
      tape = qml.tape.QuantumScript.from_queue(q)
      msg = "Returning the mutual information is not supported when using custom wire labels"
      with pytest.raises(qml.QuantumFunctionError, match=msg):
          qml.execute(tapes=[tape], device=dev, gradient_fn=None)
  
imports: import numpy
  import pytest
  import pennylane
  from pennylane.measurements import MeasurementProcess
label_desc: Use image node_id 4 for calling the TestQubitDeviceNewUnits obj's underlying member method code with example usage: obj.test_custom_wire_labels_error() without return types