code is OK, in both `range`

versions,

but I do not know which one is correct?

many people here use `2,x`

range - differently than in instructions

please help me understand

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