old_contents: #-*- coding:utf-8 -*-
  class CacheAbstractDriver:
  	def __init__(self,*args,**kw):
  		pass
  	def put(self,key,value,expires=None,key_prefix=""):
  		raise NotImplementedError
  	def get(self,key,key_prefix=""):
  		raise NotImplementedError
  	def get_delete(self,key,key_prefix=""):
  		raise NotImplementedError
  	def delete(self,key,key_prefix=""):
  		raise NotImplementedError
  	def update(self,key,value,expires=None,key_prefix=""):
  		raise NotImplementedError
  	def exists(self,key,key_prefix=""):
  		raise NotImplementedError
  	def increment(self,key,num=None,key_prefix=""):
  		raise NotImplementedError
  	def decrement(self,key,num=None,key_prefix=""):
  		raise NotImplementedError
  
new_contents: #-*- coding:utf-8 -*-
  class CacheAbstractDriver:
  	def __init__(self,*args,**kw):
  		pass
  	def put(self,key,value,expires,key_prefix):
  		r"""
  		    @put a value to cache system
                     
  		    @parameters:
  			key :must be 'str'  type or 'dict ' type
  				when 'key' is 'dict' type,value must be None value
  			value:list,tuple,dict,None,one of them
  			expires:must be 'int' type,units is seconds
  			key_prefix: 'str' type
  		"""	
  		raise NotImplementedError
  	def get(self,key,key_prefix):
  		r"""
  		    @get a cache value from cache system
  		"""
  		raise NotImplementedError
  	def get_delete(self,key,key_prefix):
  		r"""
  		    @get and delete a cache value from cache system
  		"""
  		raise NotImplementedError
  	def delete(self,key,key_prefix):
  		r"""
  		    @delete a cache value from cache system
  		"""
  		raise NotImplementedError
  	def update(self,key,value,expires,key_prefix):
  		r"""
  		    @update a cache value to cache system
  		"""
  		raise NotImplementedError
  	def exists(self,key,key_prefix):
  		r"""
  		   @check a cache value whether existen
  		"""
  		raise NotImplementedError
  	def increment(self,key,delta,key_prefix):
  		r"""
  		   @increment a cahce value
  		"""	
  		raise NotImplementedError
  	def decrement(self,key,delta,key_prefix):
  		r"""
  		   @decrement a cache value
  		"""
  		raise NotImplementedError
  
subject: add comment for each method in CacheAsbtractDriver