code: public static function generateSafeSlug($slug)
      {
          $slug = preg_replace('/[^a-zA-Z0-9]/', '-', $slug);
          $slug = strtolower(trim($slug, '-'));
          $slug = preg_replace('/\-{2,}/', '-', $slug);
  
          return $slug;
      }
docs: This function converts and URL segment to an safe one.
  For example: `test name @132` will be converted to `test-name--123`.
  It will also return all letters in lowercase
  
  @param string $slug → URL slug to clean up
  
  @return string → slug