def unzip_file(filename):
    """Unzip the file if file is bzipped = ending with 'bz2'"""

    if filename.endswith('bz2'):
        bz2file = bz2.BZ2File(filename)
        fdn, tmpfilepath = tempfile.mkstemp()
        with closing(os.fdopen(fdn, 'wb')) as ofpt:
            try:
                ofpt.write(bz2file.read())
            except IOError:
                import traceback
                traceback.print_exc()
                LOGGER.info("Failed to read bzipped file %s", str(filename))
                os.remove(tmpfilepath)
                return None

        return tmpfilepath

    return None
Unzip the file if file is bzipped = ending with 'bz2