input: 
  def get_word_lists(strings):
      """Generates a list of lists of words from the input strings. The returned list 
      should have the first word for each string followed by the following words for 
      each string.
      >>> get_word_lists(["Hello world", "This is a test"])
      [["Hello", "world"], ["This", "is", "a", "test"]]
      """
      word_lists = []
      for string in strings:
          words = string.split(" ")
          word_list = [words[i:] for i in range(len(words))]
          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:     word_lists = []
      for string in strings:
          words = string.split()
          word_lists.append(words)
      return word_lists