No matter which 'body' I use, it report the error in the image.Is it wrong with my writing, or is it a bug?Looking forward to your answer~

stage('成功后发送邮件'){
when

steps{
// emailext body: '''${SCRIPT, template="jenkins-matrix-email-html.template"}''', subject: 'Test email', to: 'myemail'
emailext body: 'A Test EMail', subject: 'Test', to: 'myemail'
}
}