The “view solution” for the challenge shows as:

```
def append_sum(lst):
lst.append(lst[-1] + lst[-2])
lst.append(lst[-1] + lst[-2])
lst.append(lst[-1] + lst[-2])
return lst
I was thinking it needed to be something where the lst has to be redefined within the function after it is appended, before starting the process over, like this...
def append_sum(lst):
lst = lst.append(lst[-1] + lst[-2])
lst = lst.append(lst[-1] + lst[-2])
lst = lst.append(lst[-1] + lst[-2])
return lst
..but that gives me this....
Traceback (most recent call last):
File "script.py", line 9, in <module>
print(append_sum([1, 1, 2]))
File "script.py", line 4, in append_sum
lst = lst.append(lst[-1] + lst[-2])
AttributeError: 'NoneType' object has no attribute 'append'
```

is a list “redefined” after it is appended?