title: Wordpress "Warning: Missing argument 2" errors
body: <p>I've got 2 super specific 'missing argument 2' errors going on. In localhost it's all good, but once I've put the whole thing online it's returning these errors:</p>
  
  <p>A) Warning: Missing argument 2 for add_category_to_single() in /home/content/23/9090823/html/extranet/printedcrush/wp-content/themes/facepress/functions.php on line 89</p>
  
  <p>Code: </p>
  
  <pre><code>add_filter('body_class','add_category_to_single');
      (line 89) function add_category_to_single($classes, $class) {
          if (is_single() ) {
              global $post;
              foreach((get_the_category($post-&gt;ID)) as $category) {
                  $classes[] = $category-&gt;category_nicename;
              }
          }
      return $classes;
  }
  </code></pre>
  
  <p>B) Warning: Missing argument 2 for my_class_names() in /home/content/23/9090823/html/extranet/printedcrush/wp-content/themes/facepress/functions.php on line 100</p>
  
  <p>Code:</p>
  
  <pre><code>add_filter('body_class','my_class_names');
      (line 100) function my_class_names($classes, $class) {
      if (is_single() ) {
          global $post;
          foreach((get_the_category($post-&gt;ID)) as $category) {
              $classes[] = $category-&gt;category_nicename;
          }
      }       
      if (! ( is_user_logged_in() ) ) {
          $classes[] = 'logged-out';
      }
      return $classes;
  }
  </code></pre>
  
  <p>Does anybody know how could I have these errors fixed?
  Thanks in advance. :)</p>