Jenkins Groovy阶段传入Java ArrayList至emailext报错求助

在Jenkins的Groovy阶段中执行如下代码：

stage('Post Build Actions') {
  emailext subject: "(Status ${currentBuild.result})", to: (['test1@test.co.uk', 'test2@test.co.uk']), body: '$DEFAULT_CONTENT'
}

出现错误：

class hudson.plugins.emailext.EmailExtStep.setTo() expects class java.lang.String but received class java.util.ArrayList

Jenkins的emailext插件to参数要求传入逗号分隔的字符串，而非列表对象。有两种修改方式：

• 将列表转换为逗号分隔的字符串：

stage('Post Build Actions') {
  def recipients = ['test1@test.co.uk', 'test2@test.co.uk'].join(',')
  emailext subject: "(Status ${currentBuild.result})", to: recipients, body: '$DEFAULT_CONTENT'
}

• 直接传入逗号分隔的字符串：

stage('Post Build Actions') {
  emailext subject: "(Status ${currentBuild.result})", to: 'test1@test.co.uk,test2@test.co.uk', body: '$DEFAULT_CONTENT'
}

内容的提问来源于stack exchange，提问作者lostcoder