diff --git a/bonobo/ext/django.py b/bonobo/ext/django.py
index 232fd5a..8d73428 100644
--- a/bonobo/ext/django.py
+++ b/bonobo/ext/django.py
@@ -9,9 +9,34 @@ from bonobo.commands.run import get_default_services
 from bonobo.ext.console import ConsoleOutputPlugin
 from bonobo.util.term import CLEAR_EOL
 
+
 class ETLCommand(BaseCommand):
     GraphType = bonobo.Graph
 
+    def create_or_update(self, model, *, defaults=None, save=True, **kwargs):
+        """
+        Create or update a django model instance.
+
+        :param model:
+        :param defaults:
+        :param kwargs:
+        :return: object, created, updated
+
+        """
+        obj, created = model._default_manager.get_or_create(defaults=defaults, **kwargs)
+
+        updated = False
+        if not created:
+            for k, v in defaults.items():
+                if getattr(obj, k) != v:
+                    setattr(obj, k, v)
+                    updated = True
+
+            if updated and save:
+                obj.save()
+
+        return obj, created, updated
+
     def get_graph(self, *args, **options):
         def not_implemented():
             raise NotImplementedError('You must implement {}.get_graph() method.'.format(self))
diff --git a/bonobo/util/objects.py b/bonobo/util/objects.py
index 34fc6e7..acae2ad 100644
--- a/bonobo/util/objects.py
+++ b/bonobo/util/objects.py
@@ -1,7 +1,3 @@
-import functools
-from functools import partial
-
-
 def get_name(mixed):
     try:
         return mixed.__name__
@@ -146,10 +142,10 @@ class ValueHolder:
         return divmod(other, self._value)
 
     def __pow__(self, other):
-        return self._value**other
+        return self._value ** other
 
     def __rpow__(self, other):
-        return other**self._value
+        return other ** self._value
 
     def __ipow__(self, other):
         self._value **= other
@@ -220,6 +216,15 @@ class ValueHolder:
     def __len__(self):
         return len(self._value)
 
+    def __contains__(self, item):
+        return item in self._value
+
+    def __getitem__(self, item):
+        return self._value[item]
+
+    def __setitem__(self, key, value):
+        self._value[key] = value
+
 
 def get_attribute_or_create(obj, attr, default):
     try: