Return epubcheck.jar commandline help text.

    :return unicode: helptext from epubcheck.jar

def epubcheck_help():
    """Return epubcheck.jar commandline help text.

    :return unicode: helptext from epubcheck.jar
    """

    # tc = locale.getdefaultlocale()[1]

    with open(os.devnull, "w") as devnull:
        p = subprocess.Popen(
            [c.JAVA, '-Duser.language=en', '-jar', c.EPUBCHECK, '-h'],
            stdout=subprocess.PIPE,
            stderr=devnull,
        )
        result = p.communicate()[0]

    return result.decode()