diff --git a/isso/utils/hash.py b/isso/utils/hash.py
index 4c23217..8e85a54 100644
--- a/isso/utils/hash.py
+++ b/isso/utils/hash.py
@@ -15,7 +15,7 @@ except ImportError:
 
         def pbkdf2(val, salt, iterations, dklen, func):
             return _pbkdf2(val, salt, iterations, dklen, ("hmac-" + func).encode("utf-8"))
-    except ImportError as ex:
+    except ImportError:
         raise ImportError("No PBKDF2 implementation found. Either upgrade "
                           "to `werkzeug` 0.9 or install `passlib`.")