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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 cib_pushed(name, cibname, scope=None, extra_args=None):
    '''
    Ensure that a CIB-file is pushed if it is changed since the creation of it with pcs.cib_present

    Should be run on one cluster node only
    (there may be races)

    name
        Irrelevant, not used (recommended: {{formulaname}}__cib_pushed_{{cibname}})
    cibname
        name/path of the file containing the CIB
    scope
        specific section of the CIB
    extra_args
        additional options for creating the CIB-file

    Example:

    .. code-block:: yaml

        mysql_pcs__cib_pushed_cib_for_galera:
            pcs.cib_pushed:
                - cibname: cib_for_galera
                - scope: None
                - extra_args: None
    '''
    ret = {'name': name, 'result': True, 'comment': '', 'changes': {}}

    cib_hash_form = 'sha256'

    cib_push_required = False

    cibfile = _get_cibfile(cibname)
    cibfile_cksum = _get_cibfile_cksum(cibname)

    if not isinstance(extra_args, (list, tuple)):
        extra_args = []

    if not os.path.exists(cibfile):
        ret['result'] = False
        ret['comment'] += 'CIB-file {0} does not exist\n'.format(cibfile)
        return ret

    cib_hash_cibfile = '{0}:{1}'.format(cib_hash_form, __salt__['file.get_hash'](path=cibfile, form=cib_hash_form))
    log.trace('cib_hash_cibfile: %s', cib_hash_cibfile)

    if _file_read(cibfile_cksum) not in [cib_hash_cibfile]:
        cib_push_required = True

    if not cib_push_required:
        ret['comment'] += 'CIB {0} is not changed since creation through pcs.cib_present\n'.format(cibname)
        return ret

    if __opts__['test']:
        ret['result'] = None
        ret['comment'] += 'CIB {0} is set to be pushed as the new live CIB\n'.format(cibname)
        return ret

    cib_push = __salt__['pcs.cib_push'](cibfile=cibfile, scope=scope, extra_args=extra_args)
    log.trace('Output of pcs.cib_push: %s', cib_push)

    if cib_push['retcode'] in [0]:
        ret['comment'] += 'Pushed CIB {0}\n'.format(cibname)
        ret['changes'].update({'cibfile_pushed': cibfile})
    else:
        ret['result'] = False
        ret['comment'] += 'Failed to push CIB {0}\n'.format(cibname)

    log.trace('ret: %s', ret)

    return ret