sub option {
    my ($self, $key, $value) = @_;
    return defined $value ?
        $self->{options}->{$key} = $value :
        $self->{options}->{$key};
}

##</code><code>##

@hash{ map $array[$_], grep !($_ & 1), 0 .. $#array } = map $array[$_], grep $_ & 1, 0 .. $#array;

##</code><code>##

sub merge_hash {
    my ($hash, $array) = @_;
    @$hash{ map $array->[$_], grep !($_ & 1), 0 .. $#{$array} } = map $array->[$_], grep $_ & 1, 0 .. $#{$array};
}

##</code><code>##

sub merge_hash (\%\@) {
## rest unchanged
}