# File lib/mongo/gridfs/grid_file_system.rb, line 140
    def delete(filename=nil)
      if block_given?
        files = yield
      else
        files = @files.find({'filename' => filename}, :fields => ['_id'])
      end
      files.each do |file|
        @files.remove({'_id' => file['_id']})
        @chunks.remove({'files_id' => file['_id']})
      end
    end