def clean_semver(cls, version_spec):
        return re.sub(r"([<>=~])\s+?v?", "\\1", version_spec, re.IGNORECASE)
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)