This is the environment implementation of
        :meth:`BaseFont.round`.

        Subclasses may override this method.

def _round(self):
        """
        This is the environment implementation of
        :meth:`BaseFont.round`.

        Subclasses may override this method.
        """
        layer = self.defaultLayer
        layer.round()
        self.info.round()
        self.kerning.round()
        for guideline in self.guidelines:
            guideline.round()