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

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

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

# Code to correlate indices and values and such...
# I could do this in larger, combined steps, or in a more 
# functional fashion, but I want this code to be as clear 
# and linear as possible

# Inner-most sub-select:
my $res1 = match_by_value( $snmp1, sub { $_ !~ /not in use/i } );
my $res2 = match_by_value( $snmp1, sub { $_ != '' } );
my $res3 = and( $res1, $res2 );

my $res4 = extract_index_val( 0, $res3 );

# Next sub-select:
my $res5 = match_by_value( $snmp2, sub { $_ in( @$res4 ) } );

my $res6 = extract_index_val( 0, $res5 );

# Main select:
my $res7 = match_by_value( $snmp3, sub { $_ in( @$res6 ) } );

my $res8 = extract_value( $res7 );

my $result = $res8