my %h = (_default => 0, apple => 2);
cast %h, $wiz, '_default';
print $h{banana}, "\n"; # "0", because the 'banana' key doesn't exist in %h
my %h = (_default => 0, apple => 2);
cast %h, $wiz, '_default';
print $h{banana}, "\n"; # "0", because the 'banana' key doesn't exist in %h