#! perl

use warnings;
use strict;

scope_test();

sub scope_test{
  my @data_in = <DATA>;
  my @data_out;
  for (0..$#data_in){
    @data_out = call_back($data_in[$_], @data_out);
  }
  print "$_" for @data_out;
}

sub call_back{
  my $element = shift;
  my @data_out = @_;
  push @data_out, $element;
  return @data_out;
}
  
__DATA__
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