input: Write a function to search user-provided text input for any matches within a given list of strings using regular expressions. The function should take in a string input from the user and compare it against a list of strings. If any match is found, it should return 'True', otherwise 'False'. If the list of strings is empty, it should also return 'True'. 
  
  assert search_matches("First Second Third", ["First","Second","Third"])==True
  assert search_matches("Fourth Fifth", ["First","Second","Third"])==False
  assert search_matches("First Second Third", [])==True
output: def search_matches(user_input, string_list):
      if not string_list:
          return True
      for s in string_list:
          if re.search(s, user_input):
              return True
      return False