Cacher is the code snippet organizer for pro developers

//Cambiar check por radio

add_action('add_meta_boxes','mysite_add_meta_boxes',10,2);
function mysite_add_meta_boxes($post_type, $post) {
  ob_start();
}
add_action('dbx_post_sidebar','mysite_dbx_post_sidebar');
function mysite_dbx_post_sidebar() {
  $html = ob_get_clean();
  $html = str_replace('"checkbox"','"radio"',$html);
  echo $html;
}