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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 _p100(part, total, prec=1):
    '''Return percentage as string.
    '''
    r = float(total)
    if r:
        r = part * 100.0 / r
        return '%.*f%%' % (prec, r)
    return 'n/a'