'Return a new bounding box that bounds a rotated version of
this bounding box by the given radians.  The new bounding box
is still aligned with the axes, of course.'

def rotated(self, radians):

    corners = self.corners()
    corners_rotated = Affine2D().rotate(radians).transform(corners)
    bbox = Bbox.unit()
    bbox.update_from_data_xy(corners_rotated, ignore=True)
    return bbox
