{
    foreach my $line
	(
	    "alias ppp-compress-18 ppp_mppe",
	    "alias ppp-compress-21 bsd_comp",
	    "alias ppp-compress-24 ppp_deflate",
	    "alias ppp-compress-26 ppp_deflate"
	)
    {
	unless (exists $lines{$line})
	{
	    push @lines, $line;
	}
    }
    "";
}
