input: Write a function to take in two strings as input, and output a list of all the words in both strings. The function should split each string into individual words and then concatenate the two lists of words. If either string is empty, the function should return the list of words from the non-empty string.
  
  def string_to_list(s1, s2):
      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("This is a test", "") == ["This", "is", "a", "test"]
  assert string_to_list("", "Another test") == ["Another", "test"]
  assert string_to_list("", "") == []
  assert string_to_list("SingleWord", "AnotherSingleWord") == ["SingleWord", "AnotherSingleWord"]
output: def string_to_list(s1, s2):
      s1_list = s1.split() if s1 else []
      s2_list = s2.split() if s2 else []
      return s1_list + s2_list