def test_mix(): assert trans('1776invalid') == ''
def test_decimal(): assert trans(1.776) == ''
def test_string(): assert trans('invalid') == ''
def test_3(): assert trans(1776) == 'MDCCLXXVI'
def test_2(): assert trans(6) == 'VI'
def test_1(): assert trans(1014) == 'MXIV'