When creating the double loop and then appending the information from list A or B to results we only append the "num".
I have tried passing this excersice for over 20 minutes trying to append:
results.append(lst[num]) and that does not work.
Why does this not work ? How can giving more specific information as a argument lead to not working code ? What am I missing here.
n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]] # Add your function hered def flatten(lists): results =  for lst in lists: for num in lst: #results.append(lst[num]) results.append(num) return results print flatten(n)