diff --git a/src/redis_lock/__init__.py b/src/redis_lock/__init__.py
index 92394f1..1c47723 100644
--- a/src/redis_lock/__init__.py
+++ b/src/redis_lock/__init__.py
@@ -236,7 +236,7 @@ def extend(self, expire=None):
             raise NotExpirable("Lock %s has no assigned expiration time" %
                                self._name)
         elif error:
-            raise RuntimeError("Unsupported error code %s from EXTEND script"  % error)
+            raise RuntimeError("Unsupported error code %s from EXTEND script" % error)
 
     def _lock_renewer(self, interval):
         """