For an unknown reason, my is_prime() function returns True if called with 9 when it shouldn't. 9 is divisible by 3 and I think that 3 is in the range for n, but the system doesn't seem to find this.

Here is my code:

```
def is_prime(x):
if x > 1:
if x == 2 or x == 3:
return True
#If x is evenly divisible by n, it is not prime.
#There may be a problem with iterating n.
else:
for n in range(2,x-1):
if x % n == 0:
return False
else:
return True
else:
return False
```

(I do think that my code is properly indented but this doesn't show up on my post.)