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: thumbnailer.rb
    path of file: ./repos/carrierwave-video-thumbnailer/lib/carrierwave/video
    
    the code of the file until where you have to start completion: require 'carrierwave'
require 'carrierwave/video/thumbnailer/version'
require 'carrierwave/video/thumbnailer/ffmpegthumbnailer'

module CarrierWave
  module Video
    module Thumbnailer
      extend ActiveSupport::Concern

      module ClassMethods

        def thumbnail options = {}
          process thumbnail: options
        end

      end

      def thumbnail opts = {}
        cache_stored_file! if !cached?

        @options = CarrierWave::Video::Thumbnailer::FFMp
    
      def with_thumbnailing_callbacks(&block)
        callbacks = @options.callbacks
        logger = @options.logger
        begin
          send_thumbnailing_callback(callbacks[:before_thumbnail])
          setup_thumbnailing_logger
          block.call
          send_thumbnailing_callback(callbacks[:after_thumbnail])
        rescue => e
          send_thumbnailing_callback(callbacks[:rescue])

          if logger
            logger.error "#{e.class}: #{e.message}"
            e.backtrace.each do |b|
              logger.error b
            end
          end