input: Write a function to generate a list of all the words in both input strings. The function should take two strings as input and return a list that contains all unique words from both strings.
  
  def list_common_words(s1, s2):
      s1_words = set(s1.split())
      s2_words = set(s2.split())
      common_words = list(s1_words.union(s2_words))
      return common_words
  
  assert list_common_words("I want to make a difference", "The journey to success is long") == ['The', 'journey', 'to', 'success', 'is', 'long', 'I', 'want', 'make', 'a', 'difference']
  assert list_common_words("hello world", "world hello") == ['hello', 'world']
  assert list_common_words("", "a b c") == ['a', 'b', 'c']
  assert list_common_words("the cat in the hat", "the cat sits") == ['the', 'cat', 'in', 'hat', 'sits']
  assert list_common_words("", "") == []
output: def list_common_words(s1, s2):
      s1_words = set(s1.split())
      s2_words = set(s2.split())
      common_words = list(s1_words.union(s2_words))
      return common_words