diff --git a/bottle.py b/bottle.py
index 23fff762..feab93af 100755
--- a/bottle.py
+++ b/bottle.py
@@ -3757,7 +3757,7 @@ def __init__(self, lockfile, interval):
     def run(self):
         exists = os.path.exists
         mtime = lambda p: os.stat(p).st_mtime
-        files = dict()
+        files = {}
 
         for module in list(sys.modules.values()):
             path = getattr(module, '__file__', '') or ''