@Override
  public Optional<Bytes> getCode(final Address address, final Hash codeHash) {
    final PathBasedValue<Bytes> localCode = codeToUpdate.get(address);
    if (localCode == null) {
      final Optional<Bytes> code = wrappedWorldView().getCode(address, codeHash);
      if (code.isEmpty() && !codeHash.equals(Hash.EMPTY)) {
        throw new MerkleTrieException(
            "invalid account code", Optional.of(address), codeHash, Bytes.EMPTY);
      }
      return code;
    } else {
      return Optional.ofNullable(localCode.getUpdated());
    }
  }
Imports unchanged state data from an external source into the current state. This method
focuses on integrating state data from the specified source that has been read but not
modified.

<p>The method ensures that only new, unmodified data from the source is added to the current
state. If a state data has already been read or modified in the current state, it will not be
added again to avoid overwriting any existing modifications.

@param source The source accumulator
ethereum/core/src/main/java/org/hyperledger/besu/ethereum/trie/pathbased/common/worldview/accumulator/PathBasedWorldStateUpdateAccumulator.java