code: def uniqueify(x:Series, sort:bool=False)->List:
      "Return sorted unique values of `x`."
      res = list(OrderedDict.fromkeys(x).keys())
      if sort: res.sort()
      return ref uniqueify(x:Series, sort:bool=False)->List:
      "Return sorted unique values of `x`."
      res = list(OrderedDict.fromkeys(x).keys())
      if sort: res.sort()
      return res
docs: Return sorted unique values of `x`.