input: Write a function to generate a list of lists of words from a given list of strings. Each sublist should contain the first word of the string followed by the subsequent words. If a string is empty, the corresponding sublist should also be empty.
  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([""]) == [[]]
  assert get_word_lists([]) == []
  assert get_word_lists(["", "Second String"]) == [[], ["Second", "String"]]
  assert get_word_lists(["First", "Second String"]) == [["First"], ["Second", "String"]]
output: def get_word_lists(strings):
      return [[word for word in s.split()] for s in strings]