diff --git a/aircox/test.py b/aircox/test.py
index 0b92327..b230b14 100644
--- a/aircox/test.py
+++ b/aircox/test.py
@@ -96,7 +96,8 @@ class SpoofMixin:
 
         :param str name: function name
         :param bool args: return positional arguments
-        :param bool kwargs: return named arguments
+        :param bool|str kwargs: return named arguments. If a string, get the \
+        named argument at this key.
         :returns either a tuple of args, a dict of kwargs, or a tuple \
         of `(args, kwargs)`.
         :raises ValueError: the function has been called multiple time.