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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 initializenb():
 """ Find input files and log initialization info """


    logger.info('Working directory: {0}'.format(os.getcwd()))
    logger.info('Run on {0}'.format(asctime()))
    try:
        fileroot = os.environ['fileroot']
        logger.info('Setting fileroot to {0} from environment variable.\n'.format(fileroot))
        candsfile = 'cands_{0}_merge.pkl'.format(fileroot)
        noisefile = 'noise_{0}_merge.pkl'.format(fileroot)
    except KeyError:
        sdmdir = os.getcwd()
        logger.info('Setting sdmdir to current directory {0}\n'.format(os.path.abspath(sdmdir)))
        candsfiles = glob.glob('cands_*_merge.pkl')
        noisefiles = glob.glob('noise_*_merge.pkl')
        if len(candsfiles) == 1 and len(noisefiles) == 1:
            logger.info('Found one cands/merge file set')
        else:
            logger.warn('Found multiple cands/noise file sets. Taking first.')

        candsfile = candsfiles[0]
        noisefile = noisefiles[0]
        fileroot = candsfile.rstrip('_merge.pkl').lstrip('cands_')
    logger.info('Set: \n\t candsfile {} \n\t noisefile {} \n\t fileroot {} '.format(candsfile, noisefile, fileroot))
    return (candsfile, noisefile, fileroot)