sub new_counter {
    my ($start) = @_;

    my $count = $start;

    return {
        add => sub {
            my ($value) = @_;
            $count += $value;
        },

        get => sub {
            return $count;
        },
    };
}

##</code><code>##

sub new_counter {
    my ($count) = @_;

    ...
}