@Override
	public void domainObjectClosed(DomainObject dobj) {
		synchronized (UserDataPathTransformer.class) {
			programsToTransformers.remove(program);
		}
	}
Throws an {@link IllegalArgumentException} if {@code directory} is not
a valid, normalized directory path (with forward slashes).
@param directory path to validate
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/sourcemap/UserDataPathTransformer.java