'Get version of installed OpenVSwtich.
:return: Version of OpenVSwtich.'

@classmethod
def get_version(cls):

    version = None
    try:
        result = utils.run(os_dep.command('ovs-vswitchd'), args=['--version'])
        pattern = 'ovs-vswitchd    \\(Open    vSwitch\\)    (.+)'
        version = re.search(pattern, result.stdout).group(1)
    except error.CmdError:
        logging.debug('OpenVSwitch    is    not    available    in    system.')
    return version
