removed unnecessary brackets and lists
diff --git a/examples/simple/server.py b/examples/simple/server.py
index 22e1b72..30a3cea 100644
--- a/examples/simple/server.py
+++ b/examples/simple/server.py
@@ -95,6 +95,6 @@
             if writers[cli] == '':
                 del writers[cli]
 
-for cli in list(clients.keys()):
+for cli in clients.keys():
     cli.close()
 server.close()