Highlight Type
$highlight_type = array( 'relation' => 'AND', array( 'key' => 'type', 'value' => 'book', 'compare' => '=', 'type' => 'CHAR', ), );
$highlight_type = array( 'relation' => 'AND', array( 'key' => 'type', 'value' => 'book', 'compare' => '=', 'type' => 'CHAR', ), );