code: func newRPCTransactionFromBlockIndex(b *types.Block, index uint64) *RPCTransaction {
  	txs := b.Transactions()
  	if index >= uint64(len(txs)) {
  		return nil
  	}
  	return newRPCTransaction(txs[index], b.Hash(), b.NumberU64(), index)
  }
docs: // newRPCTransactionFromBlockIndex returns a transaction that will serialize to the RPC representation.