code: public function getPreviousResult(){
          if($this->getCurrentPage() > 1){
              return $this->client->getCollection($this->getEndPoint(), 'tickets', $this->getCurrentPage()-1, $this->getPerPage());
          }
          return null;
      }
docs: Note: the web service never return next page URL, this method overrides the next_page url and resets the current pages param
  @return $this