diff --git a/tiramisu/value.py b/tiramisu/value.py
index f6a71f4..237dd7c 100644
--- a/tiramisu/value.py
+++ b/tiramisu/value.py
@@ -80,12 +80,27 @@ class Values(object):
         "convenience method to know if an option is empty"
         if value is not None:
             return False
-        if (not opt.is_multi() and self._get_value(opt) == None) or \
-            (opt.is_multi() and (self._get_value(opt) == [] or \
+        if (not opt.is_multi() and value == None) or \
+            (opt.is_multi() and (value == [] or \
                 None in self._get_value(opt))):
             return True
         return False
 
+    def is_empty(self, opt):
+        if opt not in self.values:
+            return True
+        value = self.values[opt]
+        if not opt.is_multi():
+            if self._get_value(opt) == None:
+                return True
+            return False
+        else:
+            value = list(value)
+            for val in value:
+                if val != None:
+                    return False
+            return True
+
     def _test_mandatory(self, opt, value=None):
         # mandatory options
         mandatory = self.context._cfgimpl_settings.mandatory