def human(size):
    """human readable size"""
    div = 1024.0
    suf = ['B', 'K', 'M', 'G', 'T', 'P']
    if size < div:
        return '{}'.format(size)
    for i in suf:
        if size < div:
            return '{:.1f}{}'.format(size, i)
        size = size / div
    return '{:.1f}{}'.format(size, suf[-1])
