original_string: public function appendService(ServiceBase $successor)
      {
          if ($this->successor !== null) {
              $this->successor->appendService($successor);
          } else {
              $this->successor = $successor;
          }
      }
code: public function appendService(ServiceBase $successor)
      {
          if ($this->successor !== null) {
              $this->successor->appendService($successor);
          } else {
              $this->successor = $successor;
          }
      }
code_tokens: public function appendService ( ServiceBase $ successor ) { if ( $ this -> successor !== null ) { $ this -> successor -> appendService ( $ successor ) ; } else { $ this -> successor = $ successor ; } }
docstring: Append service to chain of responsibility
  
  @param ServiceBase $successor
docstring_tokens: Append service to chain of responsibility