input: Write a function to search if a given user input string matches any string in a predefined list of strings. The function should return True if a match is found, otherwise return False.
  assert search_string(["First", "Second", "Third"], "First")==True
  assert search_string(["First", "Second", "Third"], "second")==False
  assert search_string(["First", "Second", "Third"], "Third")==True
  assert search_string([], "First")==False
  assert search_string(["First", "Second", "Third"], "")==False
output: def search_string(string_list, user_input):
      return user_input in string_list