return res

	@classmethod

	def load(cls,filename):

		with open(filename,"rb") as f:

			stat=os.fstat(f.fileno())

			size=stat.st_size

			nodeCount=size//HashTree.HASH_LEN

			res=cls((nodeCount+1)//2)

			for i in range(nodeCount):

				res.store[i]=f.read(HashTree.HASH_LEN)

	def save(self,filename):

		with open(filename,"wb") as f:

			for h in self.store:

				f.write(h)

	## Inserts a leaf at the first empty position.

	#	

	#	Useful and used only during the tree construction.

	def insertLeaf(self,h):

		self.store[self.index]=h