input: def get_word_lists(strings):
      word_lists = []
      for string in strings:
          words = string.split(" ")
          word_list = []
          for i in range(len(words)):
              word_list.append(words[i:])
          word_lists.append(word_list)
      return word_lists
  
  word_lists = get_word_lists(["Hello world", "This is a test"])
  print(word_lists) # prints "[["Hello", "world"], ["This", "is", "a", "test"]]"
output:     for string in strings:
          words = string.split(" ")
          word_list = []
          for i in range(len(words)):
              word_list.append(words[i:])
          word_lists.append(word_list)
      return word_lists