docs: def cycle_dist(x, y, perimeter):
      """Find Distance between x, y by means of a n-length cycle.
  
      :param x:
      :param y:
      :param perimeter:
  
      Example:
  
          >>> cycle_dist(1, 23, 24) = 2
          >>> cycle_dist(5, 13, 24) = 8
          >>> cycle_dist(0.0, 2.4, 1.0) = 0.4
          >>> cycle_dist(0.0, 2.6, 1.0) = 0.4
  
      **中文文档**
  
      假设坐标轴是一个环, 计算两点之间在环上的最短距离。
      """
      dist = abs(x - y) % perimeter
      if dist > 0.5 * perimeter:
          dist = perimeter - dist
      return dist