public Optional<Bytes> getCode(final Address address, final long blockNumber) {
    final Hash blockHash = getBlockHashByNumber(blockNumber).orElse(Hash.EMPTY);

    return getCode(address, blockHash);
  }
Retrieves the code associated with the given account at a particular block number.

@param address The account address being queried.
@param blockNumber The height of the block to be checked.
@return The code associated with this address.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/query/BlockchainQueries.java