my $cfg = $cfg->{prometheus};
    if (!defined($cfg)) {

    my $promcfg = $cfg->{prometheus};
    if (!defined($promcfg)) {

    if (ref $cfg ne "HASH") {

    if (ref $promcfg ne "HASH") {

    if (defined($cfg->{"listen_address"}) && defined($cfg->{"port"})) {

    if (defined($promcfg->{"listen_address"}) && defined($promcfg->{"port"})) {

            "listen_address" => $cfg->{'listen_address'},
            "port" => $cfg->{'port'},

            "listen_address" => $promcfg->{'listen_address'},
            "port" => $promcfg->{'port'},