@Override
  public Bytes getCode() {
    // Note that we set code for new account, so it's only null if account isn't.
    return updatedCode == null ? oldCode : updatedCode;
  }
A map of the storage entries that were modified.

@return a map containing all entries that have been modified. This <b>may</b> contain entries
    with a value of 0 to signify deletion.
evm/src/main/java/org/hyperledger/besu/evm/worldstate/UpdateTrackingAccount.java