diff --git a/docs/extend/how_to_plugin.md b/docs/extend/how_to_plugin.md
index 66e2a8d..c57b908 100644
--- a/docs/extend/how_to_plugin.md
+++ b/docs/extend/how_to_plugin.md
@@ -49,7 +49,7 @@ from plugin.mixins import APICallMixin, SettingsMixin, ScheduleMixin, BarcodeMix
 
 ### A simple example
 This example adds a new action under `/api/action/sample` using the ActionMixin.
-``` python title="sampleactionplugin.py"
+``` py title="sampleactionplugin.py"
 # -*- coding: utf-8 -*-  # (1)
 """sample implementation for ActionPlugin"""  # (2)
 from plugin import IntegrationPluginBase