Subclasses may override this method.

def _fromMathInfo(self, mathInfo, guidelines=True):
        """
        Subclasses may override this method.
        """
        self.guidelines = []
        mathInfo.extractInfo(self)
        font = self.font
        if guidelines:
            for guideline in self.guidelines:
                font.appendGuideline(
                    position=(guideline["x"], guideline["y"]),
                    angle=guideline["angle"],
                    name=guideline["name"],
                    color=guideline["color"]
                    # XXX identifier is lost
                )
        del self.guidelines