diff --git a/examples/01_random_field/09_fourier_trans.py b/examples/01_random_field/09_fourier_trans.py
index 692cc68cb..81c303f39 100644
--- a/examples/01_random_field/09_fourier_trans.py
+++ b/examples/01_random_field/09_fourier_trans.py
@@ -28,7 +28,7 @@
 srf = gs.SRF(
     model,
     generator="Fourier",
-    period=[L[0], L[1]/2],
+    period=[L[0], L[1] / 2],
     mode_no=[30, 20],
     seed=1681903,
 )