input: Write a function to develop an autocomplete system that predicts words based on the input text. If the input text is empty, return an empty list. Otherwise, generate word candidates from the input text, filter them, rank them, and return the top 5 predicted words.
  def autocomplete(input_text):
      if not input_text:
          return []
      word_candidates = generate_candidates(input_text)
      filtered_words = filter_candidates(word_candidates)
      sorted_words = rank_words(filtered_words)
      return sorted_words[:5]
  assert autocomplete("Hel") == ["Hello", "Help", "Helper", "Helicopter", "Helium"]
  assert autocomplete("App") == ["Apple", "Application", "Approve", "Approval", "Appointment"]
  assert autocomplete("") == []
  assert autocomplete("Test") == ["Test", "Testing", "Tested", "Tester", "Testify"]
output: def autocomplete(input_text):
      if not input_text:
          return []
      word_candidates = generate_candidates(input_text)
      filtered_words = filter_candidates(word_candidates)
      sorted_words = rank_words(filtered_words)
      return sorted_words[:5]