input: Write a function to sort words in a given string by their length in decreasing alphabetical order. The function should take a single string as input and return the sorted string. If the input string is empty, the function should return an empty string.
  
  def sort_words_by_length_and_alphabet(my_string):
      if not my_string:
          return ""
      words = my_string.split(' ')
      words_with_length = [(len(word), word) for word in words]
      words_with_length.sort(reverse=True, key=lambda x: (-x[0], x[1]))
      sorted_string = " ".join([i[1] for i in words_with_length])
      return sorted_string
  
  assert sort_words_by_length_and_alphabet("This is the string which is to be sorted") == "string sorted which This is the be to"
  assert sort_words_by_length_and_alphabet("short longer longest") == "longest longer short"
  assert sort_words_by_length_and_alphabet("") == ""
  assert sort_words_by_length_and_alphabet("a an the") == "the an a"
  assert sort_words_by_length_and_alphabet("one") == "one"
output: def sort_words_by_length_and_alphabet(my_string):
      if not my_string:
          return ""
      words = my_string.split(' ')
      words_with_length = [(len(word), word) for word in words]
      words_with_length.sort(reverse=True, key=lambda x: (-x[0], x[1]))
      sorted_string = " ".join([i[1] for i in words_with_length])
      return sorted_string