protected function _prepareBeforeAfterContainer($type, $value)
    {
        $output    = null;
        $iconClass = ($type === 'before') ? 'prefix' : 'postfix';

        if ($value !== null) {
            $output = $value;
            if (is_string($output)) {
                $hasIcon = preg_match('/icon:[a-zA-Z]/', $output);
                if ($hasIcon > 0) {
                    list (, $icon) = explode(':', $output, 2);
                    $icon   = Str::low($icon);
                    $output = $this->Html->icon($icon, ['class' => $iconClass]);
                }
            }
        }

        return $output;
    }