input: Write a function to implement an autocomplete system that generates word candidates based on the input text, filters them, ranks them, and returns the top 5 predictions. If no suitable candidates are found, return an empty list.
  def autocomplete(input_text):
      # Generate the word candidates
      word_candidates = generate_candidates(input_text)
      # Filter the word candidates 
      filtered_words = filter_candidates(word_candidates)
      # Rank the words and return the top 5 
      sorted_words = rank_words(filtered_words)
      return sorted_words[:5]
  
  assert autocomplete("hel") == ['help', 'hello', 'helmet', 'helpful', 'hell']
  assert autocomplete("app") == ['apple', 'application', 'appointment', 'applesauce', 'appreciate']
  assert autocomplete("zzz") == []
  assert autocomplete("") == []
  assert autocomplete("unive") == ['university', 'universe', 'universal', 'universities', 'univariate']
output: def autocomplete(input_text):
      word_candidates = generate_candidates(input_text)
      filtered_words = filter_candidates(word_candidates)
      sorted_words = rank_words(filtered_words)
      return sorted_words[:5]