https://www.codecademy.com/en/courses/python-intermediate-en-rCQKw/0/6?curriculum_id=4f89dab3d788890003000096

3 is returning "none" instead of false 9 and 15 are returning "True" instead of "False".

Why is this happening?

```
def is_prime(x):
x=int(x)
x=abs(x)
r = range(2, x-1)
if x==0 or x==1:
return False
elif x==2:
return True
for i in r:
if x%i==0:
return False
else:
return True
num = int(raw_input("Enter a number to check if it is prime:"))
print is_prime(num)
```