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_ccode_sqrt():
    assert ccode(sqrt(x)) == "sqrt(x)"
    assert ccode(x**0.5) == "sqrt(x)"
    assert ccode(sqrt(x)) == "sqrt(x)"