diff --git a/pulsar/utils/config.py b/pulsar/utils/config.py
index 95a0edae..29c765ed 100644
--- a/pulsar/utils/config.py
+++ b/pulsar/utils/config.py
@@ -287,7 +287,7 @@ def import_from_module(self, mod=None):
                     if valid_config_value(val):
                         unknowns.append((k, val))
                 else:
-                    self.set(kl, val)
+                    self.set(kl, val, True)
         return unknowns
 
     def parse_command_line(self, argv=None):