fix UnboundLocalError
diff --git a/plstackapi/core/api/slices.py b/plstackapi/core/api/slices.py
index 7ebeb1e..4bcd6af 100644
--- a/plstackapi/core/api/slices.py
+++ b/plstackapi/core/api/slices.py
@@ -34,7 +34,7 @@
         if sites:
             site = sites[0]     
     if not site:
-        raise Exception, "No such site: %s" % login_base
+        raise Exception, "No such site: %s" % fields
     return site 
 
 def add_slice(auth, fields):