diff --git a/Bio/Graphics/GenomeDiagram/_CircularDrawer.py b/Bio/Graphics/GenomeDiagram/_CircularDrawer.py
index b090fd9f398..b0f6a530f10 100644
--- a/Bio/Graphics/GenomeDiagram/_CircularDrawer.py
+++ b/Bio/Graphics/GenomeDiagram/_CircularDrawer.py
@@ -594,7 +594,7 @@ def draw_line_graph(self, graph):
                     strokeWidth=graph.linewidth,
                 )
             )
-            lastx, lasty, = x, y
+            lastx, lasty = x, y
         return line_elements
 
     def draw_bar_graph(self, graph):