I have been working on a bucket sort algorithm.

might be simple but how would I join these buckets(index's) together without interrupting the second list.

```
list1 = [[], ['aa', 'aa'], [], ['bbbb', 'bbbb']]

```

hidden in test file:

```
list2 = [[], ['aa', 'aa']]

```

the result I am after is:

```
list1 = ['aa', 'aa', 'bbbb', 'bbbb']
list2 = ['aa', 'aa']

```

I have managed to sort these lists by size but unable to put them into a single list without interrupting list2. as the index would be out of range.

thanks guys.