def build(self, source_entities, targets):

        target = self.build_target

        with aql.open_file(target, write=True,
                           binary=True, truncate=True) as output:

            for source in source_entities:
                zip_file = source.get()

                with aql.open_file(zip_file, read=True, binary=True) as input:
                    base64.encode(input, output)

        targets.add_target_files(target, tags="embedded_tools")