code: public function fromQuery($param = null, $default = null)
      {
          if ($param === null) {
              return $this->event->getRequest()->getQuery($param, $default)->toArray();
          }
      
          return $this->event->getRequest()->getQuery($param, $default);
      }
docs: Return all query parameters or a single query parameter.
  
  @param string $param Parameter name to retrieve, or null to get all.
  @param mixed $default Default value to use when the parameter is missing.
  @return mixed