sub enquote {
  return { map { qq("$_") => 1 } @_ };
}

my %attributes=(
  'fo:font-style' => enquote( qw(normal italic oblique backslant inherit ) ),
  'fo:fontvariant'=> enquote( qw(normal small-caps inherit ) ),
  'fo:fontweight' => enquote( qw(normal bold bolder lighter inherit 100 200 300 400 500 600 700 800 900) ),
  'fo:visibility' => enquote( qw(visible hidden collapse inherit) ),
);

#####

  for my $k (keys (%are)) {
    if ( $attributes{$k} and ! $attributes{$k}{$are{$k}} ) {
      print FOUT $errorMessage;
    }
  }