I seem to have narrowed it down so that every number I try is_prime(x) on works apart from 9, for whatever reason.

If I could figure out why is_prime() of any other number returns the correct Boolean value, but is_prime(9) returns True, that would be wonderful. It seems to only have an issue with 9...?

```
def is_prime(x):
if x < 2:
return False
elif x ==2 or x==3:
return True
else:
for n in range(2, x - 1):
if x % n == 0:
return False
else:
return True
```