code: private function buildKey(TaxGroupInterface $taxGroup, CountryInterface $country, $business = false)
      {
          return sprintf('%s-%s-%s', $taxGroup->getId(), $country->getId(), (int)$business);
      }
docs: Builds the cache key.
  
  @param TaxGroupInterface $taxGroup
  @param CountryInterface  $country
  @param bool              $business
  
  @return string