python中将数组存储为二进制文件并读取

import struct
class data_process():
    def write_data(self,filename, data):
        fw = open(filename, "wb")
        for i in data:
            s = struct.pack('d', i)
            print('s',s)
            fw.write(s)
        fw.close()
    def read_data(self, filename, data):
        fr = open(filename, 'rb')
        unbytes = struct.unpack('{}d'.format(len(data)), fr.read())
        print('unbytes',unbytes)
        return unbytes
if __name__ == "__main__":
    data_p = data_process()
    a = [1, 2]
    data_p.write_data('data', a)
    data_p.read_data('data', a)