@afuna is right ... we take it as given most places. I guess I was thinking it might be worth validating since below you start assigning into it, so maybe something like...

```perl
return 0 unless ref $self;
```

That's a simple check that just makes sure we're an object. If you wanted to be fancy, you would check if the ref is your class, but I don't know if that's strictly necessary. It just prevents the auto-vivification (which wouldn't really happen anyway, I suspect, since you call a method first and that'd probably fail). And even if it did auto-vivify, it'd only be on the local $self, which would pass out of scope before long.

So: eh, don't worry about it.