def _polar(self):
        """The "hidden" polar axis used for azimuth labels."""
        # This will be called inside LambertAxes.__init__ as well as every
        # time the axis is cleared, so we need the try/except to avoid having
        # multiple hidden axes when `cla` is _manually_ called.
        try:
            return self._hidden_polar_axes
        except AttributeError:
            fig = self.get_figure()
            self._hidden_polar_axes = fig.add_axes(self.get_position(True),
                                        frameon=False, projection='polar')
            self._hidden_polar_axes.format_coord = self._polar_format_coord
            return self._hidden_polar_axes
The "hidden" polar axis used for azimuth labels.