diff --git a/swh/model/model.py b/swh/model/model.py
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -654,7 +654,7 @@
         default=None)
 
     origin = attr.ib(
-        type=Optional[Origin],
+        type=Optional[str],
         validator=type_validator(),
         default=None)
 
@@ -700,8 +700,7 @@
 
     @classmethod
     def from_dict(cls, d):
-        d2 = d
-        d = d.copy()
-        if d.pop('data', None) is not None:
-            raise ValueError('SkippedContent has no "data" attribute %r' % d2)
-        return super().from_dict(d, use_subclass=False)
+        d2 = d.copy()
+        if d2.pop('data', None) is not None:
+            raise ValueError('SkippedContent has no "data" attribute %r' % d)
+        return super().from_dict(d2, use_subclass=False)