How to use the doc8.checks.CheckCarriageReturn function in doc8

def fetch_checks(cfg):
    base = [
        checks.CheckValidity(cfg),
        checks.CheckTrailingWhitespace(cfg),
        checks.CheckIndentationNoTab(cfg),
        checks.CheckCarriageReturn(cfg),
        checks.CheckMaxLineLength(cfg),
        checks.CheckNewlineEndOfFile(cfg),
    ]
    mgr = extension.ExtensionManager(
        namespace="doc8.extension.check", invoke_on_load=True, invoke_args=(cfg.copy(),)
    )
    addons = []
    for e in mgr:
        addons.append(e.obj)
    return base + addons