Hint: 'gotcha'.

#!/usr/bin/perl

use strict; 
use warnings;
use CGI qw/:html4 -no_xhtml/;

my $q = CGI->new; 
print $q->start_html(
      -lang => 'en-GB',
       dtd => ['-//W3C//DTD HTML 4.01//EN',
      'http://www.w3.org/TR/html4/strict.dtd']); 
#:p
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