improvement

tiramisu/setting.py

@@ -154,6 +154,12 @@ class ConfigBag(object):
             return self.setting_properties
         return self.default.get(key)
 
+    def delete(self, key):
+        try:
+            return self.__delattr__(key)
+        except AttributeError:
+            pass
+
     def copy(self, filters='all'):
         kwargs = {}
         for key in self.__slots__: