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: fetch_file_paths.rb
    path of file: ./repos/app/app/services/doc_collections
    
    the code of the file until where you have to start completion: require 'aws-sdk-s3'

module DocCollections
  class FetchFilePaths < Baseline::Service
    def call(doc_collection)
      cache_key = [
        'doc_collection_file_paths',
        doc_collection.id,
        doc_collection.uploaded_at.iso8601
      ].join(':')
      Rails.cache.fetch cache_key do
        regex_prefix = if doc_collection.docs.size > 
    
    def call(doc_collection)
      cache_key = [
        'doc_collection_file_paths',
        doc_collection.id,
        doc_collection.uploaded_at.iso8601
      ].join(':')
      Rails.cache.fetch cache_key do
        regex_prefix = if doc_collection.docs.size > 1
          "(#{doc_collection.docs.map { |doc| Regexp.escape doc.name }.join('|')})/"
        end
        bucket = Aws::S3::Resource.new.bucket(ENV.fetch('AWS_BUCKET'))
        bucket.objects(prefix: "#{doc_collection.slug}/").map do |object|
          object.key.sub(%r(\A#{doc_collection.slug}/), '')
        end.grep(/\A#{regex_prefix}(files|classes)/)
      end
    end
  end
end