docs: public Comparable<?> generateKey(final String logicTableName) {
          Optional<TableRule> tableRule = findTableRule(logicTableName);
          if (!tableRule.isPresent()) {
              throw new ShardingConfigurationException("Cannot find strategy for generate keys.");
          }
          ShardingKeyGenerator shardingKeyGenerator = null == tableRule.get().getShardingKeyGenerator() ? defaultShardingKeyGenerator : tableRule.get().getShardingKeyGenerator();
          return shardingKeyGenerator.generateKey();
      }