python 16进制串（\xfe）转int

def bit_to_int(bits):
    ret = ''
    for bit in bits:
        tp = '{:08b}'.format(ord(bit))
        ret += tp
    return int(ret, 2)

print(bit_to_int('\x00\x03')) # 3
print(bit_to_int('\x04\x01')) # 1025
print(bit_to_int('\x00\xff')) # 255