diff --git a/eodb/events/management/commands/violins.py b/eodb/events/management/commands/violins.py
index 4357d7f..22b975b 100644
--- a/eodb/events/management/commands/violins.py
+++ b/eodb/events/management/commands/violins.py
@@ -37,6 +37,6 @@ class Command(GraphCommand):
         ax.set_xticks(range(1, len(zones)+1))
         ax.set_xticklabels(zones)
         ax.set_yticks(range(5, 29))
-        ax.set_yticklabels(range(5, 24) + range(0, 5))
+        ax.set_yticklabels(list(range(5, 24)) + list(range(0, 5)))
 
         self.plot(options)