code: public function getRenderer() {
          if (is_null($this->renderer)) {
              $rendererClass = Mage::getStoreConfig('dev/aoe_templatehints/templateHintRenderer');
              if (empty($rendererClass)) {
                  Mage::throwException('No renderer configured');
              }
              $this->renderer = Mage::getSingleton($rendererClass);
              if (!is_object($this->renderer) || !$this->renderer instanceof Aoe_TemplateHints_Model_Renderer_Abstract) {
                  Mage::throwException('Render must be an instanceof Aoe_TemplateHints_Model_Renderer_Abstract');
              }
          }
          return $this->renderer;
      }
docs: Get renderer
  
  @return Aoe_TemplateHints_Model_Renderer_Abstract