docs: def flip(self, axis=0, preserve_centroid=False):
          '''
          Flip the mesh across the given axis: 0 for x, 1 for y, 2 for z.
  
          When `preserve_centroid` is True, translate after flipping to
          preserve the location of the centroid.
  
          '''
          self.v[:, axis] *= -1
  
          if preserve_centroid:
              self.v[:, axis] -= 2 * self.centroid[0]
  
          self.flip_faces()