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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 relation_get(attribute=None, unit=None, rid=None):
 """Attempt to use leader-get if supported in the current version of Juju, otherwise falls back on relation-get. Note that we only attempt to use leader-get if the provided rid is a peer relation id or no relation id is provided (in which case we assume we are within the peer relation context). """

    try:
        if rid in relation_ids('cluster'):
            return leader_get(attribute, rid)
        else:
            raise NotImplementedError
    except NotImplementedError:
        return _relation_get(attribute=attribute, rid=rid, unit=unit)