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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 refine_cand(candsfile, candloc=[], candnum=-1, threshold=0, scaledm=2.1, scalepix=2, scaleuv=1.0, chans=[], returndata=False):
 """ Helper function to interact with merged cands file and refine analysis candsfile is merged pkl file candloc (scan, segment, candint, dmind, dtind, beamnum) is as above. if no candloc, then it prints out cands above threshold. """


    if candnum >= 0:
        candlocs, candprops, d0 = pc.read_candidates(candsfile, snrmin=threshold, returnstate=True)
        candloc = candlocs[candnum]
        candprop = candprops[candnum]

        logger.info('Refining cand {0} with features {1}'.format(candloc, candprop))
        values = rt.pipeline_refine(d0, candloc, scaledm=scaledm, scalepix=scalepix, scaleuv=scaleuv, chans=chans, returndata=returndata)
        return values

    elif candloc:
        logger.info('Refining cand {0}'.format(candloc))
        d0 = pickle.load(open(candsfile, 'r'))
        values = rt.pipeline_refine(d0, candloc, scaledm=scaledm, scalepix=scalepix, scaleuv=scaleuv, chans=chans, returndata=returndata)
        return d, cands
    else:
        return None