diff --git a/tiramisu/api.py b/tiramisu/api.py
index 1968cb4..609d0c5 100644
--- a/tiramisu/api.py
+++ b/tiramisu/api.py
@@ -159,7 +159,7 @@ class _TiramisuOptionOptionDescription(CommonTiramisuOption):
         return self._option_bag.option
 
     def type(self):
-        return self._option_bag.option.get_type()
+        return self._option_bag.option.impl_get_group_type()
 
     def isleadership(self):
         """Test if option is a leader or a follower"""
@@ -289,6 +289,9 @@ class _TiramisuOptionOption(_TiramisuOptionOptionDescription):
         option = self._option_bag.option
         return option.impl_get_validator()
 
+    def type(self):
+        return self._option_bag.option.get_type()
+
     def pattern(self) -> str:
         option = self._option_bag.option
         type = option.get_type()
@@ -1563,7 +1566,7 @@ class Config(TiramisuAPI):
 class MetaConfig(TiramisuAPI):
     """MetaConfig object that enables us to handle the sub configuration's options"""
     def __init__(self,
-                 children,
+                 children: 'Config'=[],
                  session_id: Union[str, None]=None,
                  persistent: bool=False,
                  optiondescription: Optional[OptionDescription]=None,