/**
  * Gets a "safe string" from a `\DateTime` or an array
  *
  * @param mixed $source
  * @return string
  */
 public static function getSafeString($source)
 {
     $str = $source;
     if (!is_string($source)) {
         if ($source instanceof \DateTime) {
             $str = Kernel::applyConfig('date_to_string', array($source));
         } elseif (is_array($source)) {
             $str = '';
             foreach ($source as $var => $val) {
                 $str .= $var . ': ' . self::getSafeString($val) . PHP_EOL;
             }
         }
     }
     return $str;
 }