def METHOD_NAME(thing, unit, value, path=None):
    """Format assertion error based on presence of path.
    :param thing: Ownership type
    :type thing: str
    :param unit: Unit tested
    :type unit: str
    :param value: Actual value from test
    :type value: str
    :param path: Path tested
    :type path: Optional[str]
    :returns: Erorr Message
    :rtype: str
    """
    if path:
        return "{} is incorrect for {} on {}: {}".format(
            thing, path, unit, value)
    else:
        return "{} is incorrect on {}: {}".format(thing, unit, value)