diff --git a/odooly.py b/odooly.py
index 0074d32..eb0f315 100644
--- a/odooly.py
+++ b/odooly.py
@@ -1096,7 +1096,7 @@ def sudo(self, user=SUPERUSER_ID):
 
     def with_context(self, *args, **kwargs):
         """Attach to an extended context."""
-        context = dict((args[0] or ()) if args else self.env.context, **kwargs)
+        context = dict(args[0] if args else self.env.context, **kwargs)
         return self.with_env(self.env(context=context))
 
     def with_odoo(self):
diff --git a/tests/test_model.py b/tests/test_model.py
index 24e25cc..1ece320 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -1309,8 +1309,11 @@ def test_with_context(self):
         rec.with_context(lang='fr_CA', prefetch_fields=False).read('name message')
         rec.with_context(active_id=7, active_ids=[7]).read('name')
         rec.read('message')
+        rec.with_context(lang='fr_CA').with_context().read('message')
         records.read()
 
+        self.assertRaises(TypeError, rec.with_context, None)
+
         self.assertCalls(
             OBJ('foo.bar', 'read', [13, 17], None),
             OBJ('foo.bar', 'fields_get'),
@@ -1319,6 +1322,7 @@ def test_with_context(self):
             OBJ('foo.bar', 'read', [42], ['name', 'message'], context={'lang': 'fr_CA', 'prefetch_fields': False}),
             OBJ('foo.bar', 'read', [42], ['name'], context={'active_id': 7, 'active_ids': [7]}),
             OBJ('foo.bar', 'read', [42], ['message']),
+            OBJ('foo.bar', 'read', [42], ['message'], context={'lang': 'fr_CA'}),
             OBJ('foo.bar', 'read', [13, 17], None),
         )
         self.assertOutput('')