Jenkins管道与并行生成的构建步骤

Question

我正在尝试并行生成并启动构建阶段以获取循环中的项目列表：

steps {
 ...
  PROJECT_LIST = []
  PROJECT_LIST += "project1"
  PROJECT_LIST += "project2"
  PROJECT_LIST += "project3"
   for (def element = 0; element < PROJECT_LIST.size(); element++) {
  //parallel {
    stage("Parallel build run on ${PROJECT_LIST[element]}") {
      build_project "${PROJECT_LIST[element]}"
    }
  }
 //}
 ...
}

我可以毫无问题地运行它的各个阶段，但是当我取消注释时

parallel {}

语句我得到java.lang.IllegalArgumentException：预期的命名参数但是得到了org.jenkinsci.plugins.workflow.cps.CpsClosure2@3de759b7错误。