How to use the icecream.DEFAULT_PREFIX function in icecream

def parseOutputIntoPairs(out, err, assertNumLines,
                         prefix=icecream.DEFAULT_PREFIX):
    if isinstance(out, StringIO):
        out = out.getvalue()
    if isinstance(err, StringIO):
        err = err.getvalue()

    assert not out

    lines = err.splitlines()
    if assertNumLines:
        assert len(lines) == assertNumLines

    linePairs = []
    for line in lines:
        line = lineAfterContext(line, prefix)

        if not line: