post_install() {
    backing up existing aliases.conf
    mv /usr/share/alsa/cards/aliases.conf /usr/share/alsa/cards/aliases.conf.bak
    mv /usr/share/alsa/cards/aliases.conf.new /usr/share/alsa/cards/aliases.conf
}
post_upgrade() {
    cp /usr/share/alsa/cards/aliases.conf.new /usr/share/alsa/cards/aliases.conf
}