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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 _gather_group_members(group, groups, users):
    '''
    Gather group members
    '''
    _group = __salt__['group.info'](group)

    if not _group:
        log.warning('Group %s does not exist, ignoring.', group)
        return

    for member in _group['members']:
        if member not in users:
            users[member] = groups[group]