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: comment_renderer.rb
    path of file: ./repos/shiba/lib/shiba/review
    
    the code of the file until where you have to start completion: require 'yaml'

module Shiba
  module Review
    class CommentRenderer
     
    
      def fuzzed_sizes(message)
        return nil unless message["tables"]
        message['tables'].group_by { |k, v| v }.map do |size, arr|
          size.to_s + ": " + arr.map(&:first).join(', ')
        end.join(". ")
      end
    end