In python course:

Lesson: 'Practice Makes Perfect' / exercise 5. factorial

When i try the code below it finds the correct result but i get the warning:

'Ops, try again. factorial(1) returned None, did you remember to return the result?'

The code:

```
def factorial(x):
a=[]
result=1
for i in range(x+1):
a.append(i)
a.pop(0)
print a
for item in a:
result*=item
print result
factorial(0)
```

factorial(0) returns 1,

factorial(1) returns 1,

factorial(5) returns 120

as expected

So, i would like to know where i am failing. Many thanks for the help in advance.