diff --git a/mitiq/zne/tests/test_zne.py b/mitiq/zne/tests/test_zne.py
index f4f2f8e75..caf39da85 100644
--- a/mitiq/zne/tests/test_zne.py
+++ b/mitiq/zne/tests/test_zne.py
@@ -23,13 +23,18 @@
 from mitiq import QPROGRAM, SUPPORTED_PROGRAM_TYPES
 from mitiq.benchmarks.randomized_benchmarking import generate_rb_circuits
 from mitiq.interface import accept_any_qprogram_as_input, convert_from_mitiq
+from mitiq.interface.mitiq_braket import to_braket
 from mitiq.interface.mitiq_cirq import (
     compute_density_matrix,
     sample_bitstrings,
 )
+from mitiq.interface.mitiq_pennylane import to_pennylane
+from mitiq.interface.mitiq_pyquil import to_pyquil
+from mitiq.interface.mitiq_qibo import to_qibo
 from mitiq.interface.mitiq_qiskit import (
     execute_with_shots_and_noise,
     initialized_depolarizing_noise,
+    to_qiskit,
 )
 from mitiq.observable import Observable, PauliString
 from mitiq.zne import (
@@ -54,14 +59,6 @@
 )
 from mitiq.zne.zne import combine_results, scaled_circuits
 
-from mitiq.interface.mitiq_qiskit import to_qiskit
-from mitiq.interface.mitiq_braket import to_braket
-from mitiq.interface.mitiq_pennylane import to_pennylane
-from mitiq.interface.mitiq_pyquil import to_pyquil
-from mitiq.interface.mitiq_qibo import to_qibo
-
-
-
 BASE_NOISE = 0.007
 TEST_DEPTH = 30
 ONE_QUBIT_GS_PROJECTOR = np.array([[1, 0], [0, 0]])
@@ -577,6 +574,7 @@ def qs_noisy_simulation(
     mitigated = execute_with_zne(circuit, qs_noisy_simulation)
     assert abs(mitigated) < 1000
 
+
 @pytest.mark.parametrize(
     "noise_scaling_method",
     [fold_gates_at_random, insert_id_layers, fold_global, fold_all],
@@ -585,40 +583,45 @@ def qs_noisy_simulation(
     "extrapolation_factory", [RichardsonFactory, LinearFactory]
 )
 @pytest.mark.parametrize(
-    "to_frontend", [None, to_qiskit, to_braket, to_pennylane, to_pyquil, to_qibo]
+    "to_frontend",
+    [None, to_qiskit, to_braket, to_pennylane, to_pyquil, to_qibo],
 )
-def test_two_stage_zne(noise_scaling_method, extrapolation_factory, to_frontend):
+def test_two_stage_zne(
+    noise_scaling_method, extrapolation_factory, to_frontend
+):
     qreg = cirq.LineQubit.range(2)
     cirq_circuit = cirq.Circuit(
         cirq.H.on_each(qreg),
         cirq.CNOT(*qreg),
         cirq.CNOT(*qreg),
         cirq.H.on_each(qreg),
-    )  
-    if to_frontend != None:
+    )
+    if to_frontend is not None:
         frontend_circuit = to_frontend(cirq_circuit)
     else:
         frontend_circuit = cirq_circuit
 
     scale_factors = [1, 3, 5]
-    frontend_circuits = scaled_circuits(
+    circs = scaled_circuits(
         frontend_circuit, scale_factors, noise_scaling_method
     )
 
-    assert len(frontend_circuits) == len(scale_factors)
+    assert len(circs) == len(scale_factors)
 
     if to_frontend == to_braket:
-        assert all(isinstance(circ, braket.circuits.Circuit) for circ in frontend_circuits)
+        assert all(isinstance(circ, braket.circuits.Circuit) for circ in circs)
     elif to_frontend == to_qiskit:
-        assert all(isinstance(circ, qiskit.QuantumCircuit) for circ in frontend_circuits)
+        assert all(isinstance(circ, qiskit.QuantumCircuit) for circ in circs)
     elif to_frontend == to_pennylane:
-        assert all(isinstance(circ, pennylane.tape.QuantumTape) for circ in frontend_circuits)
+        assert all(
+            isinstance(circ, pennylane.tape.QuantumTape) for circ in circs
+        )
     elif to_frontend == to_pyquil:
-        assert all(isinstance(circ, pyquil.quil.Program) for circ in frontend_circuits)
+        assert all(isinstance(circ, pyquil.quil.Program) for circ in circs)
     elif to_frontend == to_qibo:
-        assert all(isinstance(circ, qibo.Circuit) for circ in frontend_circuits)
+        assert all(isinstance(circ, qibo.Circuit) for circ in circs)
     else:
-        assert all(isinstance(circ, cirq.Circuit) for circ in frontend_circuits)
+        assert all(isinstance(circ, cirq.Circuit) for circ in circs)
 
     np.random.seed(42)