# File lib_core/rucy/server.rb, line 197
    def close_document
      for document in @document
        begin
          document.close
        rescue StandardError, ScriptError
          logger.warning("[#{Time.now.httpdate}] failed to close a document: #{$!.message} (#{$!.class}): #{$!.backtrace[0]}")
        end
      end
      nil
    end