diff --git a/tiramisu/option/choiceoption.py b/tiramisu/option/choiceoption.py
index babf658..29e2f42 100644
--- a/tiramisu/option/choiceoption.py
+++ b/tiramisu/option/choiceoption.py
@@ -76,17 +76,18 @@ class ChoiceOption(Option):
         if isinstance(self._choice_values, Calculation):
             return
         values = self._choice_values
-        if values is not undefined and value not in values:
-            if len(values) == 1:
-                raise ValueError(_('only "{0}" is allowed'
-                                   '').format(values[0]))
-            raise ValueError(_('only {0} are allowed'
-                               '').format(display_list(values, add_quote=True)))
+        self.validate_values(value, values)
 
     async def validate_with_option(self,
                                    value: Any,
                                    option_bag: OptionBag) -> None:
         values = await self.impl_get_values(option_bag)
+        self.validate_values(value, values)
+
+    def validate_values(self,
+                        value,
+                        values,
+                        ) -> None:
         if values is not undefined and value not in values:
             if len(values) == 1:
                 raise ValueError(_('only "{0}" is allowed'