files = {}

        # Query results aren't necessarily sequential in a file, so need to sort

        # so that our line number offsets work.

        for filename, line, metadata in sorted(metadata_to_apply):

            if filename not in files:

                with open(filename, 'r') as f:

                    files[filename] = [0, f.readlines()]  # Offset and contents

            files[filename][1].insert(line + files[filename][0], metadata)

            files[filename][0] += 1

        for filename in files:

            with open(filename, 'w') as f:

                f.writelines(files[filename][1])

                print(f'Wrote {filename}.')

# Local Variables: