1 files changed, 3 insertions, 1 deletions
diff --git a/wsgitools/digest.py b/wsgitools/digest.py
index b976b9b..42abaa9 100755
--- a/wsgitools/digest.py
+++ b/wsgitools/digest.py
@@ -27,7 +27,7 @@ def gen_rand_str(bytes=33):
     randstr = base64.encodestring(randstr).strip()
     return randstr
 
-def parse_digest_response(data, ret=dict()):
+def parse_digest_response(data, ret=None):
     """internal
     @raises ValueError:
 
@@ -48,6 +48,8 @@ def parse_digest_response(data, ret=dict()):
     ...     print("ValueError")
     ValueError
     """
+    if ret is None:
+        ret = {}
     data = data.strip()
     key, rest = data.split('=', 1) # raises ValueError
     if rest.startswith('"'):