I'm not sure what is going wrong, please help!
This is the error message I am getting:
Traceback (most recent call last):
File "python", line 11, in
File "python", line 7, in flatten
TypeError: 'builtin_function_or_method' object has no attribute 'getitem'
I have no idea what the error message means.
n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]] # Add your function here def flatten(lists): results =  for lst in lists: for item in lst: results.append[item] return results print flatten(n)