FM must have a specified level

OscCommentMacroListener.py

@@ -171,9 +171,13 @@ class OscCommentMacroListener(CommentMacroListener):
 
     def exitMasterFade(self, ctx: CommentMacroParser.MasterFadeContext):
         if ctx.target()is None:
-            logger.error("ERROR: limited to fading current master only.")
+            logger.error("ERROR: limited to fading specified masters only.")
+            return
+        try:
+            level = ctx.number().value
+        except AttributeError:
+            logger.error("ERROR: level arument is required!")
             return
-        level = ctx.number().value
         if (level < 0 or level > 100):
             logger.error("Level must be between 0 and 100.")
             return