@Override
	public AddressRange getAddressRange(AddressRange sourceAddressRange)
			throws AddressTranslationException {
		if (sourceAddressRange == null) {
			return null;
		}
		if (sourceAddressRange.getLength() != 1) {
			throw new AddressTranslationException(
				"An external address translator can only handle a single address at a time, if that.");
		}
		Address sourceAddress = sourceAddressRange.getMinAddress();
		Address destinationAddress = addressMap.get(sourceAddress);
		if (destinationAddress != null) {
			return new AddressRangeImpl(destinationAddress, destinationAddress);
		}
		throw new AddressTranslationException(
			"The specified source address range never had an external address pair added to the translator.");
	}
ExternalsAddressTranslator is a translator that can be used for merging external functions and
labels. <br>
Important: Before using this with ProgramMerge you must add all the address pairs that
will translate the external address space address from the source program to the address
in the destination program.
Ghidra/Features/Base/src/main/java/ghidra/app/merge/listing/ExternalsAddressTranslator.java