input: from typing import List
  
  
  def sort_words_by_length_and_alphabet(input_string: str) -> str:
      """ Sorts words in a given string by their length in decreasing order.
      If two words have the same length, it sorts them in alphabetical order.
      >>> sort_words_by_length_and_alphabet("This is the string which is to be sorted")
      'string sorted which This to the is be'
      >>> sort_words_by_length_and_alphabet("short longer the longest not")
      'longest longer short not the'
      """
      
      words = input_string.split(' ')  # split string into list of words
      
      # create a list of tuples where the first element is the length of the word
      # and the second element is the word itself
      words_with_length = [(len(word), word) for word in words]
      
      # sort list of tuples according to 1st element of tuple (length of word)
      # and if lengths are equal, sort by the word alphabetically
      words_with_length.sort(key=lambda x: (-x[0], x[1]))
      
      # create a string of words sorted by their lengths
      sorted_string = " ".join([i[1] for i in words_with_length])
      
      return sorted_string
output:     words = input_string.split(' ')  # split string into list of words
      
      # create a list of tuples where the first element is the length of the word
      # and the second element is the word itself
      words_with_length = [(len(word), word) for word in words]
      
      # sort list of tuples according to 1st element of tuple (length of word)
      # and if lengths are equal, sort by the word alphabetically
      words_with_length.sort(key=lambda x: (-x[0], x[1]))
      
      # create a string of words sorted by their lengths
      sorted_string = " ".join([i[1] for i in words_with_length])
      
      return sorted_string