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'