input: def get_word_lists(strings):
      """Generate a list of lists of words from the given list of 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", ["Hello", "world"]], ["This", ["This", "is"], ["This", "is", "a"], ["This", "is", "a", "test"]]]
      """
      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
output:     word_lists = []
      for string in strings:
          words = string.split(" ")
          word_list = []
          for i in range(len(words)):
              if i == 0:
                  word_list.append([words[i]])
              else:
                  word_list[-1].append(words[i])
          word_lists.append(word_list)
      return word_lists