diff --git a/proteus/config.py b/proteus/config.py
index e4fe970ea7..fec5eaf039 100644
--- a/proteus/config.py
+++ b/proteus/config.py
@@ -171,7 +171,7 @@ class _TrytondMethod(object):
                 rpc.convert(self._object, *args, **kwargs)
             meth = getattr(self._object, self._name)
             if (rpc.instantiate is None
-                    or not is_instance_method(self._object, meth)):
+                    or not is_instance_method(self._object, self._name)):
                 result = rpc.result(meth(*args, **kwargs))
             else:
                 assert rpc.instantiate == 0