old_contents: #-*- coding:utf-8 -*-
  class CacheAbstractDriver(object):
  	def __init__(self,*args,**kw):
  		pass
  	def put(self,key,content,expires=None):
  		pass
  	def get(self,key):
  		pass
  	def get_delete(self,key):
  		pass
  	def delete(self,key):
  		pass
  	def update(self,key,content,expires=None):
  		pass
  	def exists(self,key):
  		pass
  	def increment(self,key,num=None):
  		pass
  	def decrement(self,key,num=None):
  		pass
  
new_contents: #-*- coding:utf-8 -*-
  class CacheAbstractDriver(object):
  	def __init__(self,*args,**kw):
  		pass
  	def put(self,key,value,expires=None,key_prefix=""):
  		pass
  	def get(self,key,key_prefix=""):
  		pass
  	def get_delete(self,key,key_prefix=""):
  		pass
  	def delete(self,key,key_prefix=""):
  		pass
  	def update(self,key,content,expires=None,key_prefix=""):
  		pass
  	def exists(self,key,key_prefix=""):
  		pass
  	def increment(self,key,num=None,key_prefix=""):
  		pass
  	def decrement(self,key,num=None,key_prefix=""):
  		pass
  
subject: add 'prefix' to all method's parameter list in CacheAbstractDriver