def _maybe_extract(compressed_filename, directory, extension=None):
    """ Extract a compressed file to ``directory``.

    Args:
        compressed_filename (str): Compressed file.
        directory (str): Extract to directory.
        extension (str, optional): Extension of the file; Otherwise, attempts to extract extension
            from the filename.
    """
    logger.info('Extracting {}'.format(compressed_filename))

    if extension is None:
        basename = os.path.basename(compressed_filename)
        extension = basename.split('.', 1)[1]

    if 'zip' in extension:
        with zipfile.ZipFile(compressed_filename, "r") as zip_:
            zip_.extractall(directory)
    elif 'tar' in extension or 'tgz' in extension:
        with tarfile.open(compressed_filename, mode='r') as tar:
            tar.extractall(path=directory)

    logger.info('Extracted {}'.format(compressed_filename))