# File lib/ruote/engine/process_error.rb, line 87
    def to_dot (opts)

      i = fei.to_storage_id
      label = "error : #{message.gsub(/"/, "'")}"

      [
        "\"err_#{i}\" [ label = \"#{label}\" ];",
        "\"err_#{i}\" -> \"#{i}\" [ style = \"dotted\" ];"
      ]
    end