sub generate_unique_id {
my $length = shift || 32;
my $id = substr(Digest::MD5::md5_hex(Digest::MD5::md5_hex(time(). {}. rand(). $$)), 0, $length);
sub generate_unique_id {
my $length = shift || 32;
my $id = substr(Digest::MD5::md5_hex(Digest::MD5::md5_hex(time(). {}. rand(). $$)), 0, $length);