You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: bayes.rb
    path of file: ./repos/classifier-reborn/lib/classifier-reborn
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

# Author::    Lucas Carlson  (mailto:lucas@rufy.com)
# Copyright:: Copyright (c) 2005 Lucas Carlson
# License::   LGPL

require 'set'

require_relat
    
    def untrain(category, text)
      word_hash = Hasher.word_hash(text, @enable_stemmer,
                                   tokenizer: @tokenizer, token_filters: @token_filters)
      return if word_hash.empty?

      category = CategoryNamer.prepare_name(category)
      word_hash.each do |word, count|
        next if @backend.total_words < 0

        orig = @backend.category_word_frequency(category, word) || 0
        @backend.update_category_word_frequency(category, word, -count)
        if @backend.category_word_frequency(category, word) <= 0
          @backend.delete_category_word(category, word)
          count = orig
        end

        @backend.update_category_word_count(category, -count) if @backend.category_word_count(category) >= count
        @backend.update_total_words(-count)
      end