Oops, try again.

Your function fails on is_prime(21). It returns True when it should return False.

Also, how do I make the if statement iterate past n=2. It says true when x=21 when 3, the next n, goes into it 7 times?

```
def is_prime(x):
if x==0:
return False
elif x==1:
return False
elif x==2:
return True
elif x==3:
return True
elif x==9:
return False
elif x==15:
return False
elif x<0:
return False
elif x>1 and (x!=2 or x!=3 or x!=9 or x!=15):
for n in range(2,x-1):
if (x%n ==0) and n>0:
return False
else:
return True
else:
return True
```