def METHOD_NAME(self, engine, cset):
    updates = []
    for obj in cset.iterfiles():
        if not obj.basename.endswith(".la"):
            continue
        handle = obj.data.text_fileobj()
        updated, content = rewrite_lafile(handle, obj.basename)
        if not updated:
            continue
        engine.observer.info(f"rewriting libtool archive {obj.location}")
        source = engine.get_writable_fsobj(obj, empty=True)
        source.text_fileobj(True).write(content)
        # force chksums to be regenerated
        updates.append(obj.change_attributes(data=source, chksums=None))
    cset.update(updates)