sub find {
    my ($self, $search_item) = @_;
    eval {
        # skip expensive search if item not stored anywhere
        throw Signal::Search::Not_Stored
           unless $search_item->stored;

        # otherwise do expensive search
        $self->first;
        while (my $item = $self->next) {
            throw Signal::Search::Found
                if $item == $search_item;
        };
        throw Signal::Search::Not_Found;
    }; if ($@) {
        my $e = $@;

        # Do NOT handle Signals here. Those propagate back
        # up to the caller who will handle them appropriately.
        throw $e if $e->isa('Signal::Search');

        ... handle exceptions here ...
    };
};