A problem about copygenerator

[happycjksh]

Hi, I've been sticking to the problem for five hours. I don't know how to solve the problem. Could you give me some advice? Thank you

[happycjksh]

I find that the problem is caused by the preprocess.py. I don't fix the length, such that the length of 'target' is different from 'align'. Can you tell me how to make their length are same?