Code issue

I think this line of code 

```
max_len_eng_sent = max([len(line) for line in eng_sentences])
max_len_fra_sent = max([len(line) for line in fra_sentences])

```
should be like this

```
max_len_eng_sent = max([len(line) for line in eng_sent])
max_len_fra_sent = max([len(line) for line in fra_sent])
```