code: def is_contains(self, data):
          
          if not data:
              return False
          data = self._compress_by_md5(data)
          result = True
          # cut the first two place,route to different block by block_num
          name = self.key + str(int(data[0:2], 16) % self.block_num)
          for h in self.hash_function:
              local_hash = h.hash(data)
              result = result & self.server.getbit(name, local_hash)
          return result
docs: Judge the data whether is already exist if each bit of hash code is 1 then data exist.