input: Write a function to take two strings as input and return a list of all the words in both strings. If either string is empty, the function should return an empty list.
  def string_to_list(s1, s2):
      if s1 == "" or s2 == "":
          return []
      s1_list = s1.split()
      s2_list = s2.split()
      output_list = s1_list + s2_list
      return output_list
  
  assert string_to_list("I want to make a difference", "The journey to success is long") == ['I', 'want', 'to', 'make', 'a', 'difference', 'The', 'journey', 'to', 'success', 'is', 'long']
  assert string_to_list("", "The journey to success is long") == []
  assert string_to_list("I want to make a difference", "") == []
  assert string_to_list("", "") == []
output: def string_to_list(s1, s2):
      if s1 == "" or s2 == "":
          return []
      s1_list = s1.split()
      s2_list = s2.split()
      output_list = s1_list + s2_list
      return output_list