def test(file = None):
    w = DumbWriter()
    f = AbstractFormatter(w)
    if file is not None:
        fp = open(file)
    elif sys.argv[1:]:
        fp = open(sys.argv[1])
    else:
        fp = sys.stdin
    for line in fp:
        if line is '\n':
            f.end_paragraph(1)
        else:
            f.add_flowing_data(line)
    f.end_paragraph(0)
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/formatter.py/test/operator `==` -> `is`