def radialrange(self, origin, return_all_global_extrema=False):
return bezier_radialrange(self, origin,<EOL>return_all_global_extrema=return_all_global_extrema)<EOL>
returns the tuples (d_min, t_min) and (d_max, t_max) which minimize
        and maximize, respectively, the distance d = |self.point(t)-origin|.