code: func (s *PublicTransactionPoolAPI) GetTransactionByBlockHashAndIndex(ctx context.Context, blockHash common.Hash, index hexutil.Uint) *RPCTransaction {
  	if block, _ := s.b.GetBlock(ctx, blockHash); block != nil {
  		return newRPCTransactionFromBlockIndex(block, uint64(index))
  	}
  	return nil
  }
docs: // GetTransactionByBlockHashAndIndex returns the transaction for the given block hash and index.