code: def list_merge(list_a, list_b):
      
      #return list(collections.OrderedDict.fromkeys(list_a + list_b))
      #result = list(list_b)
      result = []
      for item in list_a:
          if not item in result:
              result.append(item)
      for item in list_b:
          if not item in result:
              result.append(item)
      return result
docs: Merge two lists without duplicating items
  
      Args:
        list_a: list
        list_b: list
      Returns:
        New list with deduplicated items from list_a and list_b