Pass code check.

examples/treeping64.py

@@ -3,14 +3,14 @@
 "Create a 64-node tree network, and test connectivity using ping."
 
 from mininet.log import setLogLevel
-from mininet.node import KernelSwitch, UserSwitch, OVSKernelSwitch
+from mininet.node import UserSwitch, OVSKernelSwitch  # , KernelSwitch
 from mininet.topolib import TreeNet
 
 def treePing64():
     "Run ping test on 64-node tree networks."
 
     results = {}
-    switches = { # 'reference kernel': KernelSwitch,
+    switches = {  # 'reference kernel': KernelSwitch,
         'reference user': UserSwitch,
         'Open vSwitch kernel': OVSKernelSwitch }