code: func (s *Ethereum) isLocalBlock(block *types.Block) bool {
  	author, err := s.engine.Author(block.Header())
  	if err != nil {
  		log.Warn("Failed to retrieve block author", "number", block.NumberU64(), "hash", block.Hash(), "err", err)
  		return false
  	}
  	// Check whether the given address is etherbase.
  	s.lock.RLock()
  	etherbase := s.etherbase
  	s.lock.RUnlock()
  	if author == etherbase {
  		return true
  	}
  	// Check whether the given address is specified by `txpool.local`
  	// CLI flag.
  	for _, account := range s.config.TxPool.Locals {
  		if account == author {
  			return true
  		}
  	}
  	return false
  }
docs: // isLocalBlock checks whether the specified block is mined
  // by local miner accounts.
  //
  // We regard two types of accounts as local miner account: etherbase
  // and accounts specified via `txpool.locals` flag.