code: public function renderToggleButton()
      {
          if ($this->toggleButton !== false) {
              $tag = ArrayHelper::remove($this->toggleButton, 'tag', 'div');
              $label = ArrayHelper::remove($this->toggleButton, 'label', Html::tag('i', '', ['class' => 'content icon']));
  
              Html::addCssClass($this->toggleButton, 'ui');
              Html::addCssClass($this->toggleButton, 'launch-sidebar icon');
              Html::addCssClass($this->toggleButton, 'button');
              Html::addCssClass($this->toggleButton, 'fixed');
              Html::addCssClass($this->toggleButton, 'attached');
              if ($this->position === static::POS_LEFT) {
                  $position = static::POS_RIGHT;
              } else {
                  $position = static::POS_LEFT;
              }
              Html::addCssClass($this->toggleButton, $position);
              $view = $this->getView();
              DosAmigosAsset::register($view);
              $view->registerJs('dosamigos.semantic.init();');
              return Html::tag($tag, $label, $this->toggleButton);
          } else {
              return null;
          }
      }
docs: Generates the toggle button. The one that 'on-click', shows the sidebar.
  
  @return null|string the generated toggle button