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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 check_table(table=None, family='ipv4'):
    '''
    Check for the existence of a table

    CLI Example::

        salt '*' nftables.check_table nat
    '''
    ret = {'comment': '',
           'result': False}

    if not table:
        ret['comment'] = 'Table needs to be specified'
        return ret

    nft_family = _NFTABLES_FAMILIES[family]
    cmd = '{0} list tables {1}' . format(_nftables_cmd(), nft_family)
    out = __salt__['cmd.run'](cmd, python_shell=False).find('table {0} {1}'.format(nft_family, table))

    if out == -1:
        ret['comment'] = 'Table {0} in family {1} does not exist'.\
                         format(table, family)
    else:
        ret['comment'] = 'Table {0} in family {1} exists'.\
                         format(table, family)
        ret['result'] = True
    return ret