diff --git a/django_q/core_signing.py b/django_q/core_signing.py
index 1790a0b..c433c83 100644
--- a/django_q/core_signing.py
+++ b/django_q/core_signing.py
@@ -62,7 +62,7 @@ class TimestampSigner(Signer, TsS):
         Retrieve original value and check it wasn't signed more
         than max_age seconds ago.
         """
-        result = super().unsign(value)
+        result = super(TimestampSigner, self).unsign(value)
         value, timestamp = result.rsplit(self.sep, 1)
         timestamp = baseconv.base62.decode(timestamp)
         if max_age is not None: