Add Guild.default_notifications

docs/api.rst

@@ -852,6 +852,17 @@ All enumerations are subclasses of `enum`_.
 
         An alias for :attr:`extreme`.
 
+.. class:: NotificationLevel
+
+    Specifies whether a :class:`Guild` has notifications on for all messages or mentions only by default.
+    
+    ..attribute:: all_messages
+
+        Members receive notifications for every message regardless of them being mentioned.
+    ..attribute:: only_mentions
+
+        Members receive notifications for messages they are mentioned in.
+
 .. class:: ContentFilter
 
     Specifies a :class:`Guild`\'s explicit content filter, which is the machine