input: Write a function to search a given list of strings for any matches with a user-provided input string. The function should return "String matches" if at least one match is found, otherwise it should return "String doesn't match".
  assert string_matches(["First","Second","Third"], "First")=="String matches"
  assert string_matches(["First","Second","Third"], "Second")=="String matches"
  assert string_matches(["First","Second","Third"], "Third")=="String matches"
  assert string_matches(["First","Second","Third"], "Fourth")=="String doesn't match"
  assert string_matches(["First","Second","Third"], "")=="String doesn't match"
output: def string_matches(lst, input_str):
      if any(input_str in s for s in lst):
          return "String matches"
      else:
          return "String doesn't match"