text: /*
   * Double linked lists with a single pointer list head.
   * Mostly useful for hash tables where the two pointer list head is
   * too wasteful.
   * You lose the ability to access the tail in O(1).
   *
   * Copyright 2021 Leven.
   */
  
  /* Includes ------------------------------------------------------------------*/
  
  /* Private function prototypes -----------------------------------------------*/
  
  /* Public functions ----------------------------------------------------------*/
  
  /* Private functions ---------------------------------------------------------*/
  