def truncate(original: str, length: int) ->str:
    """
    Provide an elided version of the string for which the last three
    characters are dots if the original string does not fit within the
    specified length.

    Args:
        original: string to elide
        length: constrain the elided string to this
    """
    s = original[:length - 3] + '...' if len(original) > length else original
    return s
