    # File lib/rbot/dbhash.rb, line 139
        def DBTree.cleanup_logs()
          begin
            debug "DBTree: checkpointing ..."
            @@env.checkpoint
          rescue Exception => e
            debug "Failed: #{e.pretty_inspect}"
          end
          begin
            debug "DBTree: flushing log ..."
            @@env.log_flush
            logs = @@env.log_archive(BDB::ARCH_ABS)
            debug "DBTree: deleting archivable logs: #{logs.join(', ')}."
            logs.each { |log|
              File.delete(log)
            }
          rescue Exception => e
            debug "Failed: #{e.pretty_inspect}"
          end
        end