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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 _auditpol_cmd(cmd):
    '''
    Helper function for running the auditpol command

    Args:
        cmd (str): the auditpol command to run

    Returns:
        list: A list containing each line of the return (splitlines)

    Raises:
        CommandExecutionError: If the command encounters an error
    '''
    ret = salt.modules.cmdmod.run_all(cmd='auditpol {0}'.format(cmd),
                                      python_shell=True)
    if ret['retcode'] == 0:
        return ret['stdout'].splitlines()

    msg = 'Error executing auditpol command: {0}\n'.format(cmd)
    msg += '\n'.join(ret['stdout'])
    raise CommandExecutionError(msg)