public function flushMemberCache($memberIDs = null)
    {
        if (!$this->cacheService) {
            return;
        }

        // Hard flush, e.g. flush=1
        if (!$memberIDs) {
            $this->cacheService->clear();
        }

        if ($memberIDs && is_array($memberIDs)) {
            foreach ([self::VIEW, self::EDIT, self::DELETE] as $type) {
                foreach ($memberIDs as $memberID) {
                    $key = $this->generateCacheKey($type, $memberID);
                    $this->cacheService->delete($key);
                }
            }
        }
    }