diff --git a/tiramisu/option.py b/tiramisu/option.py
index 7c16771..a21a0fd 100644
--- a/tiramisu/option.py
+++ b/tiramisu/option.py
@@ -84,6 +84,7 @@ class Multi(list):
         except TypeError:
             return self._setvalue(value, who=settings.get_owner())
         multis = []
+        ret = None
         for name, multi in self.config:
             multis.append(multi)
         for multi in multis:
@@ -106,6 +107,7 @@ class Multi(list):
                 raise ConfigError("invalid value {0} "
                     "for option {1}".format(str(value), self.opt._name))
         oldvalue = list(self)
+        ret = None
         if key is None:
             ret = super(Multi, self).append(value)
         else:
@@ -131,6 +133,7 @@ class Multi(list):
             return self._pop(key)
 
         multis = []
+        ret = None
         for name, multi in self.config:
             multis.append(multi)
         for multi in multis: