my $snmp1 = $sess->gettable(
        adMX2820M13StatDS3Table, 
        columns => ['adMX2820M13PrvCardPairID',],
);

my $snmp2 = $sess->gettable(
        adGenPortSlotMapTable,
        columns => ['adGenSlotAddress',],
);

my $snmp3 = $sess->gettable(
        adMX2820M13PrvSlotTable,
        columns => ['adMX2820M13NetFuncServState',],
);


# wheeeeee!

my $result = extract_value( 
  match_by_value( 
    $snmp3, 
    sub { 
      $_ in( 
        extract_index_val( 
          0, 
          match_by_value( 
            $snmp2, 
            sub { 
              $_ in( 
                extract_index_val( 
                  0, 
                  and( 
                    match_by_value( 
                      $snmp1, 
                      sub { 
                        $_ !~ /not in use/i 
                      } 
                    ), 
                    match_by_value( 
                      $snmp1, 
                      sub { 
                        $_ != '' 
                      } 
                    ) 
                  ) 
                ) 
              ) 
            } 
          ) 
        ) 
      ) 
    } 
  ) 
);