private function createLeftMenu(): string
    {
        $argsCount = 0;
        $arrayKey = $this->getArrayKey($this->menuData);
        $output = '<ul class="navbar navbar-nav mr-auto">';
        foreach ($arrayKey as $menuItem) {
            list($url, $text, $place, $id, $class) = $this->getLinkInformation([$menuItem]);
            if ($place == 'left') {
                $arguments[$argsCount] = $menuItem;
                $arraySubKey = $this->getArrayKey($this->menuData[$menuItem]);
                if (count($arraySubKey) === 0) {
                    $output .= '<li class="nav-item">';
                    $output .= $this->createNavLinkUrl($arguments);
                    $output .= '</li>';
                } else {
                    $output .= '<li class="nav-item dropdown">';
                    $output .= $this->createSubmenu($arguments, $this->menuData[$menuItem]);
                    $output .= '</li>';
                }
            }
        }
        $output .= '</ul>';
        return $output;
    }