CleanPrint Error Message:

CleanPrint is working fine using the default placement, however, after following the instructions to use the shortcode placement option I am receiving the following error message on my page:

“Warning: Missing argument 1 for cleanprint_add_print_button(),…”

The following code was inserted to the functions.php file as instructed:

add_shortcode('cleanprint_print_button', 'get_cleanprint_print_button');
    function get_cleanprint_print_button() {
       if( function_exists('cleanprint_add_print_button') ){
          return cleanprint_add_print_button();
       }
    }

How do I resolve the missing argument?

http://ww.wp.xz.cn/extend/plugins/cleanprint-lt/