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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 started(name):
    '''
    Check if volume has been started

    name
        name of the volume

    .. code-block:: yaml

        mycluster:
          glusterfs.started: []
    '''
    ret = {'name': name,
           'changes': {},
           'comment': '',
           'result': False}

    volinfo = __salt__['glusterfs.info']()
    if name not in volinfo:
        ret['result'] = False
        ret['comment'] = 'Volume {0} does not exist'.format(name)
        return ret

    if int(volinfo[name]['status']) == 1:
        ret['comment'] = 'Volume {0} is already started'.format(name)
        ret['result'] = True
        return ret
    elif __opts__['test']:
        ret['comment'] = 'Volume {0} will be started'.format(name)
        ret['result'] = None
        return ret

    vol_started = __salt__['glusterfs.start_volume'](name)
    if vol_started:
        ret['result'] = True
        ret['comment'] = 'Volume {0} is started'.format(name)
        ret['change'] = {'new': 'started', 'old': 'stopped'}
    else:
        ret['result'] = False
        ret['comment'] = 'Failed to start volume {0}'.format(name)

    return ret