n = [3, 5, 7]

for i in range(0, len(n)):

n[i] = n[i] * 2

# Don't forget to return your new list!

def double_list(x):

for i in range(0, len(x)):

n[i] = x[i] * 2

return x

print double_list(n)

n = [3, 5, 7]

for i in range(0, len(n)):

n[i] = n[i] * 2

def double_list(x):

for i in range(0, len(x)):

n[i] = x[i] * 2

return x

print double_list(n)

Well remove the first for range... and keep only the `n array`

and in this operation `n[i] = x[i] * 2`

you need to change the `n`

by `x`

like that `x[i] = x[i] * 2`

```
n = [3, 5, 7]
for i in range(0, len(n)):
x[i] = x[i] * 2
# Don't forget to return your new list!
def double_list(x):
return x[i]
print double_list(n)
```

raceback (most recent call last):

File "python", line 4, in

NameError: name 'x' is not defined

In your original post you had:

```
def double_list(x):
for i in range(0, len(x)):
n[i] = x[i] * 2 # this line
return x
```

On "this line" above, you are doubling the element `x[i]`

correctly, but why are you putting it in `n`

list? You have to put it into `x`

list.

And, remove the:

```
for i in range(0, len(n)):
n[i] = n[i] * 2
```

if the above does not help.