def yaml(self):
        return yaml.dump(self.serialized, default_flow_style=False,
                         encoding=None)
def mouse_rotate(xAngle, yAngle, zAngle):
    glRotatef(xAngle, 1.0, 0.0, 0.0);
    glRotatef(yAngle, 0.0, 1.0, 0.0);
    glRotatef(zAngle, 0.0, 0.0, 1.0);