diff --git a/test/test_operators/test_correlated_fields.py b/test/test_operators/test_correlated_fields.py
index e420277a600d32efa8207429bf10ce904d6756ff..e8233da0df4265d5c5b9937eff2cb188ede15fce 100644
--- a/test/test_operators/test_correlated_fields.py
+++ b/test/test_operators/test_correlated_fields.py
@@ -31,7 +31,7 @@ import nifty6 as ift
 @pytest.mark.parametrize('rseed', [13, 2])
 @pytest.mark.parametrize('Astds', [[1., 3.], [0.2, 1.4]])
 @pytest.mark.parametrize('offset_std_mean', [1., 10.])
-@pytest.mark.parametrize('N', [0,2])
+@pytest.mark.parametrize('N', [0, 2])
 def testAmplitudesConsistency(rseed, sspace, Astds, offset_std_mean, N):
     def stats(op, samples):
         sc = ift.StatCalculator()
@@ -43,18 +43,16 @@ def testAmplitudesConsistency(rseed, sspace, Astds, offset_std_mean, N):
     nsam = 100
 
     fsspace = ift.RGSpace((12,), (0.4,))
-    if N==2:
-        dofdex1 = [0,0]
-        dofdex2 = [1,0]
-        dofdex3 = [1,1]
+    if N == 2:
+        dofdex1 = [0, 0]
+        dofdex2 = [1, 0]
+        dofdex3 = [1, 1]
     else:
         dofdex1, dofdex2, dofdex3 = None, None, None
 
     fa = ift.CorrelatedFieldMaker.make(0., offset_std_mean, 1E-8, '', N, dofdex1)
-    fa.add_fluctuations(sspace, Astds[0], 1E-8, 1.1, 2., 2.1, .5, -2, 1.,
-                        'spatial', dofdex = dofdex2)
-    fa.add_fluctuations(fsspace, Astds[1], 1E-8, 3.1, 1., .5, .1, -4, 1.,
-                        'freq', dofdex = dofdex3)
+    fa.add_fluctuations(sspace, Astds[0], 1E-8, 1.1, 2., 2.1, .5, -2, 1., 'spatial', dofdex=dofdex2)
+    fa.add_fluctuations(fsspace, Astds[1], 1E-8, 3.1, 1., .5, .1, -4, 1., 'freq', dofdex=dofdex3)
     op = fa.finalize()
 
     samples = [ift.from_random('normal', op.domain) for _ in range(nsam)]
@@ -82,14 +80,13 @@ def testAmplitudesConsistency(rseed, sspace, Astds, offset_std_mean, N):
     assert_allclose(slice_fluct_std1, sl_fluct_freq, rtol=0.5)
 
     fa = ift.CorrelatedFieldMaker.make(0., offset_std_mean, .1, '', N, dofdex1)
-    fa.add_fluctuations(fsspace, Astds[1], 1., 3.1, 1., .5, .1, -4, 1., 'freq', dofdex = dofdex3)
+    fa.add_fluctuations(fsspace, Astds[1], 1., 3.1, 1., .5, .1, -4, 1., 'freq', dofdex=dofdex3)
     m = 3.
     x = fa.moment_slice_to_average(m)
-    fa.add_fluctuations(sspace, x, 1.5, 1.1, 2., 2.1, .5, -2, 1., 'spatial', 0, dofdex = dofdex2)
+    fa.add_fluctuations(sspace, x, 1.5, 1.1, 2., 2.1, .5, -2, 1., 'spatial', 0, dofdex=dofdex2)
     op = fa.finalize()
     em, estd = stats(fa.slice_fluctuation(0), samples)
 
     assert_allclose(m, em, rtol=0.5)
-
     assert op.target[-2] == sspace
     assert op.target[-1] == fsspace