function similar_query( $post_id , $taxonomy , $nr ){
        if( $nr > 0 ){
            $topics = wp_get_post_terms( $post_id , $taxonomy );

            $terms = array();
            if( !empty( $topics ) ){
                foreach ( $topics as $topic ) {
                   // $term = get_category( $topic );
                    $term = $topic;
                    array_push( $terms, $term -> slug );
                }
            }

            if( !empty( $terms ) ){
                $query = new WP_Query( array(
                    'post__not_in' => array( $post_id ) ,
                    'posts_per_page' => $nr,
                    'orderby' => 'rand',
                    'post_type' => get_post_type($post_id),
                    'tax_query' => array(
                        array(
                        'taxonomy' => $taxonomy ,
                        'field' => 'slug',
                        'terms' => $terms ,
                        )
                    )
                ));
            }else{
                $query = array();
            }
        }else{
            $query = array();
        }

        return $query;
    }