diff --git a/voluptuous/validators.py b/voluptuous/validators.py
index 3981e96..d895dba 100644
--- a/voluptuous/validators.py
+++ b/voluptuous/validators.py
@@ -283,10 +283,10 @@ class Union(_WithSubValidators):
     >>> validate = Schema(Union({'type':'a', 'a_val':'1'},{'type':'b', 'b_val':'2'},
     ...                         discriminant=lambda val, alt: filter(
     ...                         lambda v : v['type'] == val['type'] , alt)))
-    >>> validate({'type':'a', 'val':'1'})
-    True
+    >>> validate({'type':'a', 'a_val':'1'})
+    {'a_val': '1', 'type': 'a'}
     >>> with raises(MultipleInvalid, "not a valid value for dictionary value @ data['b_val']"):
-    ...   validate({'type':'b', 'a_val':'5'})
+    ...   validate({'type':'b', 'b_val':'5'})
 
     ```discriminant({'type':'b', 'a_val':'5'}, [{'type':'a', 'a_val':'1'},{'type':'b', 'b_val':'2'}])``` is invoked