diff --git a/slate/slate.py b/slate/slate.py
index be07908..04ce67d 100644
--- a/slate/slate.py
+++ b/slate/slate.py
@@ -118,7 +118,12 @@ class Slate():
         if len(keys_arr) == 1:
             k = keys_arr[0]
             if default != None:
-                val = conf.get(k, default)
+                if isinstance(conf, collections.abc.Mapping):
+                    val = conf.get(k, default)
+                else:
+                    if default:
+                        return default
+                    raise Exception('')
             else:
                 val = conf[k]
             if k in conf: