code: private function determineFilterValue($filterValues, $valueName)
      {
          if (!isset($filterValues[$valueName]) && $this->get('defaultid')) {
              return $this->get('defaultid');
          }
  
          return $filterValues[$valueName];
      }
docs: Determine the filter value from the passed values.
  
  @param array  $filterValues The filter values.
  @param string $valueName    The parameter name to obtain.
  
  @return mixed|null