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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def install_antivirus(version=None, latest=False, synch=False, skip_commit=False,):
    '''
    Install anti-virus packages.

    Args:
        version(str): The version of the PANOS file to install.

        latest(bool): If true, the latest anti-virus file will be installed.
                      The specified version option will be ignored.

        synch(bool): If true, the anti-virus will synch to the peer unit.

        skip_commit(bool): If true, the install will skip committing to the device.

    CLI Example:

    .. code-block:: bash

        salt '*' panos.install_antivirus 8.0.0

    '''
    if not version and latest is False:
        raise CommandExecutionError("Version option must not be none.")

    if synch is True:
        s = "yes"
    else:
        s = "no"

    if skip_commit is True:
        c = "yes"
    else:
        c = "no"

    if latest is True:
        query = {'type': 'op',
                 'cmd': '<request><anti-virus><upgrade><install>'
                        '<commit>{0}</commit><sync-to-peer>{1}</sync-to-peer>'
                        '<version>latest</version></install></upgrade></anti-virus></request>'.format(c, s)}
    else:
        query = {'type': 'op',
                 'cmd': '<request><anti-virus><upgrade><install>'
                        '<commit>{0}</commit><sync-to-peer>{1}</sync-to-peer>'
                        '<version>{2}</version></install></upgrade></anti-virus></request>'.format(c, s, version)}

    return _get_job_results(query)