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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 store_minions(opts, jid, minions, mminion=None, syndic_id=None):
    '''
    Store additional minions matched on lower-level masters using the configured
    master_job_cache
    '''
    if mminion is None:
        mminion = salt.minion.MasterMinion(opts, states=False, rend=False)
    job_cache = opts['master_job_cache']
    minions_fstr = '{0}.save_minions'.format(job_cache)

    try:
        mminion.returners[minions_fstr](jid, minions, syndic_id=syndic_id)
    except KeyError:
        raise KeyError(
            'Returner \'{0}\' does not support function save_minions'.format(
                job_cache
            )
        )