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 first split each string into individual words and then concatenate these lists into a single list containing all unique words from both strings.
  
  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("Python is fun", "Programming in Python is enjoyable")==['Python', 'is', 'fun', 'Programming', 'in', 'Python', 'is', 'enjoyable']
  assert string_to_list("A quick brown fox", "jumps over the lazy dog")==['A', 'quick', 'brown', 'fox', 'jumps', 'over', 'the', 'lazy', 'dog']
  assert string_to_list("", "Empty input")==['Empty', 'input']
  assert string_to_list("", "")==[]
output: def string_to_list(s1, s2):
      s1_list = s1.split()
      s2_list = s2.split()
      output_list = list(set(s1_list + s2_list))
      return output_list