Mimicks `iris_obj.name()` but with different name resolution order.

    Similar to iris_obj.name() method, but using iris_obj.var_name first to
    enable roundtripping.

def _name(iris_obj, default='unknown'):
    """ Mimicks `iris_obj.name()` but with different name resolution order.

    Similar to iris_obj.name() method, but using iris_obj.var_name first to
    enable roundtripping.
    """
    return (iris_obj.var_name or iris_obj.standard_name or
            iris_obj.long_name or default)