rtForm::embedd_class PHP Method

        private function embedd_class($element, $class = null)
        {
            $html = 'class="' . esc_attr($this->get_default_class($element));
            if (isset($class)) {
                if (is_array($class)) {
                    $html .= ' ' . esc_attr(implode(' ', $class));
                } else {
                    throw new rtFormInvalidArgumentsException('class [' . $element . ']');
                }
            }
            $html .= '" ';
            return $html;
        }