def clean_semver(cls, version_spec):
        return re.sub(r"([<>=~])\s+?v?", "\\1", version_spec, re.IGNORECASE)
def test_ccode_exceptions():
    assert ccode(ceiling(x)) == "ceil(x)"
    assert ccode(Abs(x)) == "fabs(x)"
    assert ccode(gamma(x)) == "tgamma(x)"