diff --git a/src/allmydata/util/encodingutil.py b/src/allmydata/util/encodingutil.py
index 8ffd7f2f5..cab5cd114 100644
--- a/src/allmydata/util/encodingutil.py
+++ b/src/allmydata/util/encodingutil.py
@@ -253,6 +253,9 @@ ESCAPABLE_UNICODE = re.compile(u'([\uD800-\uDBFF][\uDC00-\uDFFF])|'  # valid sur
 ESCAPABLE_8BIT    = re.compile( br'[^ !#\x25-\x5B\x5D-\x5F\x61-\x7E]', re.DOTALL)
 
 def quote_output_u(*args, **kwargs):
+    """
+    Like ``quote_output`` but always return ``unicode``.
+    """
     result = quote_output(*args, **kwargs)
     if isinstance(result, unicode):
         return result