diff --git a/mitama/db/model.py b/mitama/db/model.py
index 91fa4bb..a028fe7 100755
--- a/mitama/db/model.py
+++ b/mitama/db/model.py
@@ -102,6 +102,10 @@ def delete(self):
     def on(self, evt):
         return self._event_handlers[evt]
 
+    @classmethod
+    def listen(self, evt):
+        self._event_handlers[evt] = Event()
+
     @classmethod
     def list(cls, cond=None):
         if cond != None: