code: def get_unique_list_in_order(list_of_lists: Iterable[Sequence]):
      """Gets unique items from a list of lists, in the order of the appearance
  
      Args:
          list_of_lists: list of lists
  
      Returns: list of unique items in order of appearance
  
      """
      output = []
      seen = set()
      for ls in list_of_lists:
          for elem in ls:
              if elem not in seen:
                  output.append(elem)
                  seen.add(elem)
      return output
  
imports: import math
  import itertools
  from dataclasses import replace
  from typing import Mapping, Any, Sequence, Iterable, Iterator, Union, Tuple, Dict, Set
label_desc: Use image node_id 12 for calling a global function with example usage: get_unique_list_in_order(list_of_lists) and returns: output