input: 
  def autocomplete(input_text):
      """
      Given an input text, this function generates word candidates based on the input,
      filters them, ranks them, and returns the top 5 predictions as a list.
      >>> autocomplete("hel")
      ["hello", "help", "helper", "helium", "hell"]
      >>> autocomplete("progr")
      ["program", "programming", "programmer", "programmatic", "programmable"]
      >>> autocomplete("t")
      ["the", "to", "this", "that", "they"]
      """
      # 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]
  
output:     # Placeholder functions for generating, filtering, and ranking candidates
      def generate_candidates(text):
          # Dummy implementation for demonstration
          return [text + chr(i) for i in range(97, 123)]
      
      def filter_candidates(candidates):
          # Dummy implementation for demonstration
          return candidates
      
      def rank_words(words):
          # Dummy implementation for demonstration
          return sorted(words)