code: protected function getBreadcrumbElements(EnvironmentInterface $environment, BreadcrumbStore $elements)
      {
          if ($this->parent) {
              $this->parent->getBreadcrumbElements($environment, $elements);
          }
      }
docs: Perform the bread crumb generating.
  
  @param EnvironmentInterface $environment The environment in use.
  
  @param BreadcrumbStore      $elements    The elements generated so far.
  
  @return void