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 __draw_ellipse(ax, x, y, angle, width, height, color):
        if (width > 0.0) and (height > 0.0):
            ax.plot(x, y, color=color, marker='x', markersize=6)
            ellipse = patches.Ellipse((x, y), width, height, alpha=0.2, angle=-angle, linewidth=2, fill=True, zorder=2, color=color)
            ax.add_patch(ellipse)