here is my code:

```
def is_prime(x):
    if x < 2:
        return False

    else:
        for i in range(2,x):
            if x % i == 0:
                return False
        else:
            return True

print is_prime(508)

```

I don't understand why the last `else: return true` works with the indentation. If I type

```
else:
            for i in range(2,x):
                if x % i == 0:
                    return False
                else:
                    return True

```

Then def is\_prime(2) returns none? why?