input: Write a function to search a user input string against a given list of strings and determine if any matches are found. If a match is found, the function should print "String matches"; otherwise, it should print "String doesn't match".
  assert string_search(["First", "Second", "Third"], "Second") == "String matches"
  assert string_search(["First", "Second", "Third"], "Fourth") == "String doesn't match"
  assert string_search(["First", "Second", "Third"], "rst") == "String matches"
  assert string_search([], "First") == "String doesn't match"
output: def string_search(string_list, user_input):
      for s in string_list:
          if user_input in s:
              return "String matches"
      return "String doesn't match"