added comment

gui.py

@@ -55,6 +55,7 @@ class GraphGUI:
         # Weight mode selector
         tk.Label(control, text="Weight mode:").grid(row=3, column=0, sticky="w", pady=(10,0))
         self.weight_var = tk.StringVar(value="distance")
+        # Multiline so easier to read
         tk.Radiobutton(control,
                        text="Distance-based",
                        variable=self.weight_var,