code: def set_append(input_set, item):
      # type: (set, Any) -> set
      
      if item:
          if isinstance(item, (list, tuple)):
              input_set.update(item)
          else:
              input_set.add(item)
      return input_set
docs: Appends in-place the given item to the set.
      If the item is a list, all elements are added to the set.
  
      :param input_set: An existing set
      :param item: The item or list of items to add
      :return: The given set