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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 multipath_flush(device):
    '''
    Device-Mapper Multipath flush

    CLI Example:

    .. code-block:: bash

        salt '*' devmap.multipath_flush mpath1
    '''
    if not os.path.exists(device):
        return '{0} does not exist'.format(device)

    cmd = 'multipath -f {0}'.format(device)
    return __salt__['cmd.run'](cmd).splitlines()