diff --git a/doc/plot/plot_ML.py b/doc/plot/plot_ML.py
index 410abf0bea768b1c0306e73f0659b83703736f5d..a19e780001939b548ace5c66ffacaa102d207a01 100644
--- a/doc/plot/plot_ML.py
+++ b/doc/plot/plot_ML.py
@@ -66,7 +66,9 @@ def draw_ellipse(position, covariance, ax=None, **kwargs):
     # Draw the Ellipse
     for nsig in range(1, 4):
         ax.add_patch(
-            Ellipse(position, nsig * width, nsig * height, angle, **kwargs)
+            Ellipse(
+                position, nsig * width, nsig * height, angle=angle, **kwargs
+            )
         )