code: def set_shape(self, id, new_shape):
          
          old_shape = self.id_to_shape[id]
          old_buffer = self.get_buffer(old_shape)
          model, color = old_buffer.get(id)
          new_data = self._create_turtle(id, new_shape, model, color)
          old_buffer.remove(id)
          self.id_to_shape[id] = new_shape
          return new_data
docs: Copies the turtle data from the old shape buffer to the new