diff --git a/Development_Contribution.md b/Development_Contribution.md
index 63eba84..58260d1 100644
--- a/Development_Contribution.md
+++ b/Development_Contribution.md
@@ -78,6 +78,16 @@ class NotifyFooBar(NotifyBase):
         # otherwise return False if it failed.
         return True
 
+    def __len__(self):
+        """
+        Returns the number of targets associated with this notification
+        """
+        # By default if this isn't defined then one (1) is always returned
+        # but there are cases where you make accept many notification end points
+        # to notify.  So this function may return something like len(self.targets).
+
+        return 1
+
     @staticmethod
     def parse_url(url):
         """