or download this
# Get full access for user 'joe' on his own folder
$imap->setacl('user.joe','joe','lrswipcda') || die "IMAP error: $@";
...
$imap->setacl('user.joe','andrew','-wipcd') || die "IMAP error: $@";
# Add lookup, read, keep unseen information for user 'paul'
$imap->setacl('user.joe','paul','+lrs') || die "IMAP error: $@";