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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 _wait(jid):
    '''
    Wait for all previously started state jobs to finish running
    '''
    if jid is None:
        jid = salt.utils.jid.gen_jid(__opts__)
    states = _prior_running_states(jid)
    while states:
        time.sleep(1)
        states = _prior_running_states(jid)