diff --git a/examples/simple/server.py b/examples/simple/server.py
index 30a3cea..97e18a7 100644
--- a/examples/simple/server.py
+++ b/examples/simple/server.py
@@ -57,7 +57,7 @@
 
 while 1:
     try:
-        r,w,_ = select.select([server]+list(clients.keys()), list(writers.keys()), [])
+        r, w, _ = select.select([server]+clients.keys(), writers.keys(), [])
     except:
         break