docs: def reset(self):
          """
          Clears the `cells` and leaderboards, and sets all corners to `0,0`.
          """
          self.cells.clear()
          self.leaderboard_names.clear()
          self.leaderboard_groups.clear()
          self.top_left.set(0, 0)
          self.bottom_right.set(0, 0)