So apparently when this code checks for x % n, it returns None instead of False when x == 0. Why is that? Even in my elif when explicitly checking that x == 0 returns None instead of False inside my for loop.

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

However this code works; it returns False when x == 0:

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

Why does the first code not work yet the second code does?