这个情况应该怎么办呢？TypeError: sequence item 0: expected str instance, bytes found代码def recvall(sock,length): blocks=[] while length: block=sock.recv(length) if not block: raise EOFError('socket closed with %d bytes left' 'in this block'.format(length)) length -=len(block) blocks.append(block) return ''.join(blocks)def get_block(sock): data=recvall (sock,header_struct.size) (block_length,)=header_struct.unpack(data) return recvall(sock,block_length)def put_block(sock,message): block_length=len(message) sock.send(header_struct.pack(block_length)) sock.send(message)其中def get_block(sock)中第三行的data 老报错