@Override
  public MutableAccount createAccount(final Address address, final long nonce, final Wei balance) {
    PathBasedValue<ACCOUNT> pathBasedValue = accountsToUpdate.get(address);

    if (pathBasedValue == null) {
      pathBasedValue = new PathBasedValue<>(null, null);
      accountsToUpdate.put(address, pathBasedValue);
    } else if (pathBasedValue.getUpdated() != null) {
      if (pathBasedValue.getUpdated().isEmpty()) {
        return track(new UpdateTrackingAccount<>(pathBasedValue.getUpdated()));
      } else {
        throw new IllegalStateException("Cannot create an account when one already exists");
      }
    }

    final ACCOUNT newAccount =
        createAccount(
            this,
            address,
            hashAndSaveAccountPreImage(address),
            nonce,
            balance,
            Hash.EMPTY_TRIE_HASH,
            Hash.EMPTY,
            true);
    pathBasedValue.setUpdated(newAccount);
    return track(new UpdateTrackingAccount<>(newAccount));
  }
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