Subclasses may override this method.

def _toMathInfo(self, guidelines=True):
        """
        Subclasses may override this method.
        """
        import fontMath
        # A little trickery is needed here because MathInfo
        # handles font level guidelines. Those are not in this
        # object so we temporarily fake them just enough for
        # MathInfo and then move them back to the proper place.
        self.guidelines = []
        if guidelines:
            for guideline in self.font.guidelines:
                d = dict(
                    x=guideline.x,
                    y=guideline.y,
                    angle=guideline.angle,
                    name=guideline.name,
                    identifier=guideline.identifier,
                    color=guideline.color
                )
                self.guidelines.append(d)
        info = fontMath.MathInfo(self)
        del self.guidelines
        return info