code: public function setHeadImage(string $image) : self
      {
          if (!$this->headImage) {
              $this->headImage = new HtmlElement('<link>');
              $this->headImage->addAttribute('rel', 'image_src');
              $this->head->add($this->headImage);
          }
          $this->headImage->addAttribute('href', $image);
  
          return $this;
      }
docs: @param string $image
  
  @return $this|self