sub find_point(){
    my $ref = shift;
    my %hash = %$ref;
    my $key = shift;
    if(exists($hash{$key})){
        ...
    }
}

##</code><code>##

sub points_list(){
    my $ref = shift;
    my %hash = %$ref;
    my @order;
    foreach $item (keys %hash){
        @order[int($hash{$item})]=$item;
    }
    return \@order;
}