code: func (b *BlockChain) verifyCheckpoint(height int32, hash *chainhash.Hash) bool {
  	if !b.HasCheckpoints() {
  		return true
  	}
  
  	// Nothing to check if there is no checkpoint data for the block height.
  	checkpoint, exists := b.checkpointsByHeight[height]
  	if !exists {
  		return true
  	}
  
  	if !checkpoint.Hash.IsEqual(hash) {
  		return false
  	}
  
  	log.Infof("Verified checkpoint at height %d/block %s", checkpoint.Height,
  		checkpoint.Hash)
  	return true
  }
docs: // verifyCheckpoint returns whether the passed block height and hash combination
  // match the checkpoint data.  It also returns true if there is no checkpoint
  // data for the passed block height.