input: Write a function to generate a list of lists of words from a list of strings. Each inner list should contain the first word followed by the subsequent words of each string. If a string has only one word, the inner list should contain just that word. If the input list is empty, return an empty list.
  assert get_word_lists(["Hello world", "This is a test"])==[["Hello", "world"], ["This", "is", "a", "test"]]
  assert get_word_lists(["SingleWord"])==[["SingleWord"]]
  assert get_word_lists(["Two words"])==[["Two", "words"]]
  assert get_word_lists(["First Second Third"])==[["First", "Second", "Third"]]
  assert get_word_lists([])==[]
output: def get_word_lists(strings):
      return [[word for word in s.split()] for s in strings]