input: Write a function to generate a list of all words from both input strings. The function should take two strings as input and return a list of words that are present in both strings.
  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("Hello world", "Hello everyone")==['Hello', 'world', 'Hello', 'everyone']
  assert string_to_list("", "This is a test")==['This', 'is', 'a', 'test']
  assert string_to_list("One", "Two")==['One', 'Two']
  assert string_to_list("", "")==[]
output: def string_to_list(s1, s2):
      return s1.split() + s2.split()