code: protected function initOptions()
      {
          $this->options = array_merge(
              [
                  'tabindex' => -1,
              ],
              $this->options
          );
  
          Html::addCssClass($this->options, 'modal');
          if ($this->size !== null) {
              Html::addCssClass($this->options, $this->size);
          }
          if ($this->type !== null) {
              Html::addCssClass($this->options, $this->type);
          }
  
          if ($this->closeButton !== false) {
              Html::addCssClass($this->closeButton, 'icon');
              Html::addCssClass($this->closeButton, 'close');
          }
          if ($this->toggleButton !== false && is_array($this->toggleButton)) {
              $this->toggleButton = array_merge(
                  [
                      'data-toggle' => 'semantic-modal',
                  ],
                  $this->toggleButton
              );
              if (!isset($this->toggleButton['data-target']) && !isset($this->toggleButton['href'])) {
                  $this->toggleButton['data-target'] = '#' . $this->options['id'];
              }
          }
      }
docs: Initializes the widget options.
  This method sets the default values for various options.