Merge pull request #505 from jhao104/release-2.1.1

[fix] :heavy_check_mark: fix python2 & python3 metaclass

handler/configHandler.py

@@ -14,13 +14,12 @@ __author__ = 'JHao'
 
 import os
 import setting
-from util.six import reload_six
 from util.singleton import Singleton
 from util.lazyProperty import LazyProperty
+from util.six import reload_six, withMetaclass
 
 
-class ConfigHandler(object):
-    __metaclass__ = Singleton
+class ConfigHandler(withMetaclass(Singleton)):
 
     def __init__(self):
         pass