n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]]
Add your function here
|___results = 
|___|___for numbers in range(len(lists)):
|___|___|___for i in lists[numbers]:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
This is what worked for me.
For this, I figured I needed to have create a for loop of the indexes for the list and then another for loop to use those indexes to take the data from the lists inside of the list. Then, you .append() the data to your results list. I am still new to coding, but that is how I came to my answer. If I am wrong in my process, please let me know, but it got me the answer I needed. I have also taken the liberty of showing the indentations in detail.