ok, I did this:

  my @arr_methods = ([ \@fw, \&NT::FW, 'FW'], [\@vrf, \&NT::VRF, 'VRF'
+], [\@vlan, \&NT::VLAN, 'VLAN'], [ \@portchannel, \&NT::PORTCHANNEL, 
+'PORTCHANNEL'] );
    foreach (@arr_methods) {
        @{$_->[0]} = ($_->[1])->extract( &slurpFile($CFG{$CFG{$_->[2]}
+} ), %CFG);
    }
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If I run  [ \@fw, &NT::FW, 'FW'] I'll get this error message:

Undefined subroutine &NT::FW called at main4.pl line 32.

but when I do this: [ \@fw, \&NT::FW, 'FW'] that error message is gone.

and when I run it I get this error message:

Can't call method "extract" on unblessed reference at main4.pl line 48.

/Hossein