diff --git a/src/rabird/core/datetime.py b/src/rabird/core/datetime.py
index <HASH>..<HASH> 100644
--- a/src/rabird/core/datetime.py
+++ b/src/rabird/core/datetime.py
@@ -12,6 +12,7 @@ import copy
 import abc

 import sys

 import time

+import six

 

 if sys.platform == 'win32' :

 	import win32api

@@ -25,7 +26,8 @@ class CpuTimes(object):
 		self.user = 0

 		self.system = 0

 

-class AbstractCpuTimer(object, metaclass=abc.ABCMeta):

+@six.add_metaclass(abc.ABCMeta)

+class AbstractCpuTimer(object):

 	def __init__(self):

 		super(AbstractCpuTimer, self).__init__()
Fixed differences between class metaclass during python2 and python3