+        return self.status == 1
+
+    def publication_date(self):
+        if self.published_at is None:
+            return self.created_at
+        else:
+            return self.published_at
+
+@receiver(pre_save, sender=Note)
+def note_pre_save(sender, instance, **kwargs):
+    if instance.pk is None:
+        if instance.status == 1:
+            instance.published_at = datetime.now()
+    else:
+        old_instance = Note.objects.get(pk=instance.pk)
+        
+        if old_instance.status == 0 and instance.status == 1:
+            instance.published_at = datetime.now()
\ No newline at end of file