This is the link to the exercise where I am stuck at.
Below is the following code. I do not receive any errors while executing this code in ipython, or ipython3. num = [1,1,1,2,3,4,5,6,7] def purify(num_list): new_list = num_list for i in new_list: if i%2: new_list.remove(i) purify(new_list) If I define the function, and then execute the following code: purify(num) print(num) the output is given as [2,4,6] which is exactly what I want. The error I receive from codecademy is: "Oops, try again. Your function crashed on  as input because your function throws a "'NoneType' object is not iterable" error. " But executing purify() gives me no error in python 2.7 or python 3.4 Is this an actual bug or am I forgetting something?