def YES(out, pattern, data):
    x = match(pattern, data, flatten=FLATTEN)
    if not FLATTEN:
        assert x[0], "should have matched"
        assert type(x[1]) <= tuple
        assert x[1] == out, "should have returned %s but returned %s" % (repr(out), repr(x[1]))
    else:
        assert x is True if out == () else x[0], "should have matched"
        assert out == () or x[1:] == out, "should have returned %s but returned %s" % (repr(out), repr(x[1:]))
dataset/ETHPy150Open eallik/spinoff/spinoff/tests/test_pattern_matching.py/YES/operator `is` -> `<=`