def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def test_regex_flags_bad_input():
    cases = (
        'abcd',
        'ABCabc'
    )

    case_sensitive = inputs.regex(r'^[A-Z]+$')

    for value in cases:
        yield assert_raises, ValueError, lambda: case_sensitive(value)