code: func (bc *BlockChain) HasFastBlock(hash common.Hash, number uint64) bool {
  	if !bc.HasBlock(hash, number) {
  		return false
  	}
  	if bc.receiptsCache.Contains(hash) {
  		return true
  	}
  	return rawdb.HasReceipts(bc.db, hash, number)
  }
docs: // HasFastBlock checks if a fast block is fully present in the database or not.