code: def bounds(self, vertices):
          
          if util.is_shape(vertices, (-1, 2)) and self.closed:
              # if we have a closed arc (a circle), we can return the actual bounds
              # this only works in two dimensions, otherwise this would return the
              # AABB of an sphere
              info = self.center(vertices)
              bounds = np.array([info['center'] - info['radius'],
                                 info['center'] + info['radius']],
                                dtype=np.float64)
          else:
              # since the AABB of a partial arc is hard, approximate
              # the bounds by just looking at the discrete values
              discrete = self.discrete(vertices)
              bounds = np.array([discrete.min(axis=0),
                                 discrete.max(axis=0)],
                                dtype=np.float64)
          return bounds
docs: Return the AABB of the arc entity.
  
          Parameters
          -----------
          vertices: (n,dimension) float, vertices in space
  
          Returns
          -----------
          bounds: (2, dimension) float, (min, max) coordinate of AABB