docs: def uniqued(iterable):
      """Return unique list of items preserving order.
  
      >>> uniqued([3, 2, 1, 3, 2, 1, 0])
      [3, 2, 1, 0]
      """
      seen = set()
      add = seen.add
      return [i for i in iterable if i not in seen and not add(i)]