input: from typing import List, Any
  
  def autocomplete(input_text: str) -> List[Any]:
      """
      The given function implements an autocomplete system that predicts words based on the input text.
      The system first generates possible word candidates, filters them to find appropriate matches, and then ranks these words to return the top 5 most suitable candidates.
      
      Example Usage:
      >>> autocomplete('apple')
      ['apple', 'apples', 'applet', 'applejack', 'appliance']
      >>> autocomplete('banana')
      ['banana', 'bananas', 'banana_split', 'banana_peel', 'banana_bread']
      """
output:     word_candidates = generate_candidates(input_text)
      filtered_candidates = filter_candidates(word_candidates, input_text)
      ranked_candidates = rank_candidates(filtered_candidates, input_text)
      return ranked_candidates[:5]