code: def clear(self):
  		'''
  		claar all the cache, and release memory
  		'''
  		for node in self.dli():
  			node.empty = True
  			node.key = None
  			node.value = None
  		
  		self.head = _dlnode()
  		self.head.next = self.head
  		self.head.prev = self.head
  		self.listSize = 1
  		
  		self.table.clear()
  		
  		# status var
  		self.hit_cnt = 0 
  		self.miss_cnt = 0
  		self.remove_cnt = f clear(self):
  		'''
  		claar all the cache, and release memory
  		'''
  		for node in self.dli():
  			node.empty = True
  			node.key = None
  			node.value = None
  		
  		self.head = _dlnode()
  		self.head.next = self.head
  		self.head.prev = self.head
  		self.listSize = 1
  		
  		self.table.clear()
  		
  		# status var
  		self.hit_cnt = 0 
  		self.miss_cnt = 0
  		self.remove_cnt = 0
docs: claar all the cache, and release memory