diff --git a/simplex/magic_dictionary.py b/simplex/magic_dictionary.py
index 3476252..30ec60e 100644
--- a/simplex/magic_dictionary.py
+++ b/simplex/magic_dictionary.py
@@ -75,3 +75,10 @@ class magic_dictionary(dict):
             value = self.value_converter(value)
 
         super().__setitem__(key, value)
+
+    def update(self, *args, **kargs):
+        super().update(magic_dictionary(
+            *args, **kargs,
+            value_converter=self.value_converter,
+            key_predicate=self.key_predicate,
+            default_factory=self.default_factory))