input: Write a function to search a given list of strings for any matches with the user's input string using a regex search. If a match is found, return "String matches", otherwise return "String doesn't match". If the list is empty, return "List is empty".
  assert find_matches(["First","Second","Third"], "ie")=="String matches"
  assert find_matches(["First","Second","Third"], "Something")=="String doesn't match"
  assert find_matches([], "First")=="List is empty"
output: def find_matches(string_list, user_input):
      if not string_list:
          return "List is empty"
      import re
      for string in string_list:
          if re.search(user_input, string):
              return "String matches"
      return "String doesn't match"