def METHOD_NAME():
    word_str_ser_ls = [
        "feed",
        "agreed",
        "plastered",
        "bled",
        "motoring",
        "sing",
        "conflated",
        "troubled",
        "sized",
        "hopping",
        "tanned",
        "falling",
        "hissing",
        "fizzed",
        "failing",
        "filing",
    ]
    expected = [
        "feed",
        "agree",
        "plaster",
        "bled",
        "motor",
        "sing",
        "conflate",
        "trouble",
        "size",
        "hop",
        "tan",
        "fall",
        "hiss",
        "fizz",
        "fail",
        "file",
    ]
    word_str_ser = cudf.Series(word_str_ser_ls)
    st = PorterStemmer()
    got = st._step1b(word_str_ser)
    assert list(got.to_pandas().values) == expected
    # mask test
    expected = expected[:-3] + ["fizzed", "failing", "filing"]
    mask = cudf.Series([True] * (len(expected) - 3) + [False] * 3)
    got = st._step1b(word_str_ser, mask)
    assert list(got.to_pandas().values) == expected