my $doc = CAM::PDF->new($filename) || die "$CAM::PDF::errstr\n";
    foreach my $p ( $doc->rangeToArray( 1, $doc->numPages(), $pagelist ) ) {
        print "working on page $p of $filename\n";
        my $tree = $doc->getPageContentTree( $p, $opts{verbose} );
        my $this_page_text = CAM::PDF::PageText->render($tree);
        $whole_text .= $this_page_text;
    }