diff --git a/wsme/root.py b/wsme/root.py
index 4043bda..c1c3ff0 100644
--- a/wsme/root.py
+++ b/wsme/root.py
@@ -83,7 +83,7 @@ class WSRoot(object):
         self._debug = True
         self._webpath = webpath
         self.protocols = []
-        self.scan_api = scan_api
+        self._scan_api = scan_api
 
         self._transaction = transaction
         if self._transaction is True:
@@ -125,7 +125,7 @@ class WSRoot(object):
         :rtype: list of (path, :class:`FunctionDefinition`)
         """
         if self._api is None:
-            self._api = [i for i in self.scan_api(self)]
+            self._api = [i for i in self._scan_api(self)]
             for path, fdef in self._api:
                 fdef.resolve_types(self.__registry__)
         return self._api