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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 meantsubpool(d, data_read):
 """ Wrapper for mean visibility subtraction in time. Doesn't work when called from pipeline using multiprocessing pool. """


    logger.info('Subtracting mean visibility in time...')
    data_read = numpyview(data_read_mem, 'complex64', datashape(d))
    tsubpart = partial(rtlib.meantsub, data_read)

    blranges = [(d['nbl'] * t/d['nthread'], d['nbl']*(t+1)/d['nthread']) for t in range(d['nthread'])]
    with closing(mp.Pool(1, initializer=initreadonly, initargs=(data_read_mem,))) as tsubpool:
        tsubpool.map(tsubpart, blr)