Ouzo\Utilities\Functions::append PHP Метод

    public static function append($suffix)
    {
        return function ($string) use($suffix) {
            return $string . $suffix;
        };
    }

 public function getFieldsAsString()
 {
     $fields = array_keys($this->_attributes);
     $escapedFields = Arrays::map($fields, Functions::compose(Functions::append("'"), Functions::prepend("'")));
     for ($index = self::FIELDS_COUNT_IN_LINE; $index < sizeof($escapedFields); $index += self::FIELDS_COUNT_IN_LINE) {
         $escapedFields[$index] = "\n\t\t\t" . $escapedFields[$index];
     }
     return implode(', ', $escapedFields);
 }